MX2013014626A - Phytochemical disinfectants for lettuce (lactuca sativa). - Google Patents

Abstract

The present invention describes compositions for effectively disinfecting and/or preserving vegetable origin food polluted with pathogen and spoilage microorganisms. The aforementioned compositions contain extracts derived from plants with antimicrobial activity, which may act by themselves or in combination with other disinfecting agents, such as organic acids and chlorine compounds, and surfactants such as polysorbate 80. The compositions of the invention are able to remove or inactivate the microbial pollution, including that of pathogen microorganisms, in lettuce without altering the nutritious and/or sensorial properties therein.

Description

DISINFECTANTS F1T0QÜÍMIC0S FOR LETTUCE f Lactuca sativa) TECHNICAL FIELD OF THE INVENTION The present invention relates to the development of formulations containing phytochemicals present in plants and which are used as disinfectants and preservatives for foods, for example of vegetable and animal origin; more particularly to aqueous formulations based on extracts of chalices of Jamaica (Hibiscus sabdariffa), the method by which it is obtained and its uses as an effective formulation to eliminate pathogenic bacteria from fruits and vegetables, but with the highest effectiveness for lettuces (Lactuca sativa) STATE OF THE ART Lettuce is an agricultural product widely consumed throughout the world. In Mexico it is one of the main agricultural products, with a little more than 17 thousand hectares dedicated to its sowing. The most important types of lettuce that are sown, both in the open field and in protected agriculture, are: Orejona (the most produced), Romana, Iceberg, Boston, Italian, Cos, Baby, Butterhead, Cutting, Stalk, Latin among others (Sagarpa, 2013).

However, along with the increase in lettuce consumption there have been outbreaks of diseases caused by bacteria associated with the consumption of lettuce (CDC, 2012). For example, in 2012 lettuce was the vehicle in a multi-state outbreak, that is, it affected several states in the American union, the microorganism involved in this outbreak was Escherichia coli 0157: H7 (CDC, 2012).

This type of outbreaks has provoked a strict regulation for producers that export lettuce to the United States (USA, for its acronym in Spanish).

English); and it has frequently meant retention of shipments of lettuce on the border, partial or total closure of the export of this product to the USA and economic losses by producers by not complying with microbiological standards.

It should be noted that although in Mexico there are no reports of disease outbreaks of microbial etiology associated with consumption of lettuce, due to poor hygiene practices that generally occur during the cultivation, harvest, transport and marketing of lettuce, participation is expected. of these raw products in disease outbreaks. One fact that supports this observation is the frequency with which Salmonella strains and Escherichia coli pathogenic groups have recently been isolated from lettuce salads ready for consumption in Mexico (Castañeda-Ramírez et al., 2011; Rosas et al., 2012).

The recent outbreaks of food diseases associated with lettuce created the need to determine the sources of contamination of lettuce and to understand the survival and / or growth of pathogenic microorganisms in lettuce; These have led to the development of innovative control technologies. In general, the pathogens in lettuce could be controlled by preventing contamination during the growing and harvesting of the products, also by using disinfectants with antimicrobial power in the harvested product, and by storing the lettuce low temperature. However, the disinfection of lettuce has been identified as the most important stage for the microbial innocuousness of raw lettuce.

In general, lettuce is not consumed directly as it is harvested. After the harvest either in the field or in the industry (and even in the home) they receive diverse treatments that tend to favor their conservation and / or harmlessness. The application of washing and disinfection of lettuce improves its microbial image. However, it is difficult to safely achieve inactivation or removal of pathogenic microorganisms even under extreme conditions of treatments that do not damage sensory to the lettuce.

The prevention of lettuce contamination is also a control strategy because the growth of pathogens is not required to cause disease. Thus, the additional control measures can be of value. It should be noted that the behavior of pathogenic microorganisms in lettuce is affected by the location of the pathogen in the product, the quality of the lettuce, storage temperature, type of packaging, and relative humidity. The lettuce leaves usually have few nutrients on their surface which limits the growth of pathogens during storage at room temperature or refrigeration.

However, it should be noted that pathogenic microorganisms such as Salmonella or E. coli 0157: H7 are able to survive for a long time on the surface of lettuce leaves both in refrigeration and at room temperature (Changa and Fang, 2007; Kroupitski et al. ., 2009). In addition once on lettuce the pathogenic bacteria how Salmonella could produce extracellular polymers in the leaves of the lettuce which leads to the formation of a biofilm that can protect them against disinfectants (Kroupitski et al., 2009); This behavior of pathogenic microorganisms has been observed in different vegetables such as tomatoes (Iturriaga et al., 2007).

A fact to be noted is that pathogenic microorganisms such as Salmonella or E. coll 0157: H7, for example, are capable of multiplying in chopped or cut lettuce, increasing their concentration significantly and making food much more dangerous (Changa and Fang, 2007).

Pathogenic microorganisms on the surface of lettuce leaves can contaminate the internal tissues and infiltrate and later during the cutting of the leaves could contaminate the chopped product and grow in it (Changa and Fang, 2007). Several research findings indicate that bacterial pathogens can infiltrate plant products, such as lettuce leaves (Kroupitski et al., 2009; Bartz, 1982; Guo et al., 2002; Ibarra-Sanchez et al., 2004; Zhuang and Beuchat 1995) when there is a temperature differential between the vegetable product and the wash water and by the hydrostatic pressure when the plants are submerged in the receiving tank (Bartz, 1982, Bartz and Showalter, 1981).

Bacterial infiltration increases in raw vegetables in the presence of wounds and punctures. Infiltrated pathogens are not eliminated by normal washing practices. The main benefit of the addition of antimicrobial chemicals (such as chemical disinfectants based on hypochlorite or based on organic acids) to the washing water of lettuce is the control of the spread of pathogens, their inactivation and / or avoiding their infiltration to the leaves of lettuce. However, the chemical disinfectants currently available have limited benefits over plant products, such as lettuce. The antimicrobial effect of solutions of hypochlorite, hydrogen peroxide, peracetic acid and electrolyzed water on its ability to reduce pathogens in vegetable products during the washing process has been studied. However, it has been concluded that these treatments have a limited effect on pathogenic microorganisms, presumably because the active agents do not have sufficient contact with the pathogenic microorganisms on the raw plant products.

The disinfection process refers to the physical destruction of microorganisms whose activity compromises the safety or sensory characteristics of a food. The effect can be achieved through physical means or chemical, being its effectiveness in terms of microorganisms (type and number), the substrate on which they are (presence of organic matter), the structure of the material (which allows direct access of the germicide to microorganisms) and the germicide ( concentration, temperature and contact time) (Fernández, 2000). In the disinfection process, the germicidal substance participates in chemical reactions, so that the greater the number of microorganisms, the greater the demand of the agent to achieve a total inactivation of the population. Susceptibility to a specific germicide varies among microorganisms; some are inactivated from the first moment of contact, while at the other extreme there may be survivors. Finally, it must be borne in mind that among microorganisms it is possible to select strains with increasing resistance to the effect of a specific germicidal agent. As a result, over time, very high concentrations of the disinfectant are required at the initials to reach the same level of inactivation (Fernández, 2000).

Different studies show that the disinfection treatments of raw agricultural products often have a weak or limited effect. For example, washing and disinfection with 200 mg / L of active chlorine (hypochlorite), iodine (iodophor), chlorine dioxide or 100 mg / L of a commercial product based on grapefruit seed extract (citricidal) reduced the content of alfalfa sprouts in only 1-2 logi0; the decrease in S. typhi or V. cholerae 01 inoculated in the laboratory was not greater than 1.5 logio CFU / g (Castro-Rosas and Escartín, 1999).

The food industry has a variety of germicidal agents. Its virtues and limitations require carefully selecting those that best suit each particular need (Fernández, 2000). The inactivation of pathogenic bacteria in food processing plants is a basic requirement to control them and prevent their access to the finished product (Álvarez, 1998).

The common thing is that a germicide is considered effective when it shows capacity to inactivate at least 3 Logio of a microorganism suspension in 30s (Fernández, 2000).

Chlorine-based solutions are a cheap disinfectant available as hypochlorite or in its slow-release forms (chloramines, for example) (Lelieveld et al., 2013). Hypochlorites have a broad spectrum of antibacterial activity, although they are less effective against spores than against non-spore-forming bacteria and have a low effect against mycobacteria (Russell et al., 2004). Chlorine solutions such as sodium hypochlorite or chlorine dioxide are widely used by the food industry as a disinfectant. Both are strong oxidants that act at the level of membranes and other cellular constituents (Harmon et al., 1987). However, the first has the disadvantage of reacting easily with organic matter, so it is inactivated faster. In the second, the interference is minimal (Castro-Rosas and Escartin, 1999). The main disadvantage of sodium hypochlorite is that humidity, heat, light and especially the presence of organic matter increase the rate of loss of free chlorine. The germicidal activity of chlorine has generally been attributed to hypochlorous acid (HOCI), which is generated in aqueous solutions of sodium hypochlorite and other chlorine-containing compounds.

The disinfectants can be incorporated into the wash water and in this way contribute to the reduction of the microbial load. The effectiveness of hypochlorite is not only affected by the exposure time and the concentration of free chlorine, but also by other factors such as temperature, pH, type of strain, as well as the presence and type of organic matter (Álvarez, 1998). However, some authors they point out that the efficiency of hypochlorite in the reduction of pathogenic microorganisms present in vegetables is limited (Adams et al., 1997).

Chemical compounds derived from chlorine, iodine and silver have been typically used as vegetable disinfectants, such as lettuce. However, recently several studies show that the disinfection treatments with these compounds are inefficient in the elimination or reduction of the levels of microbial pathogens. For this reason, many countries have abandoned the use of hypochlorite or iodine solutions for the disinfection of raw vegetables.

Organic acids have traditionally been used as food preservatives or in solutions for disinfecting raw vegetables. Its antimicrobial effect is exerted through the undissociated form causing a low pH.

Acetic acid is a harmless substance; there are no official limits for daily intake in man. When acetic acid is incorporated into a food, two effects are expressed, one acidulant and another condom. A concentration of 1-2% inhibits almost all of the total flora within reasonably high initial load limits. At 0.1% acts on most pathogens and sporulated; 0.5% has an effect on toxigenic fungi. The efficacy of acetic acid against some specific pathogens has been evaluated using some foods as a medium. The published reports are often difficult to compare because the acid concentrations have been variables expressed as percentage, molarity or final pH of the acidified assay medium. The antimicrobial activity depends on the exposure time, temperature, type of acid, acid concentration, dissociation level and pH (Harmon et al., 1987). However, the general results show that the effectiveness of acetic acid increases as the concentration increases, the pH decreases, the temperature increases and the load increases. microbial decreases (Harmon et al., 1987). Among bacteria, Gram-positive are usually more resistant than Gram-negative bacteria (Rameshkumar et al., 2007). Bacterial spores and viruses are more resistant than vegetative cells. However, organic acids have also shown little effectiveness in disinfecting raw vegetables (Fernández, 2000).

Recent research indicates that antimicrobial chemicals in the vapor phase can significantly reduce pathogen populations on the surface of vegetables. The use of 5 mg / liter of chlorine dioxide gas for 1 h was significantly more effective against Salmonella in the peduncle scar of tomatoes that were aqueous solutions of 200 ppm sodium hypochlorite (2 min exposure) and 1200 ppm acidified sodium hypochlorite (2 min exposure) (Yuk et al., 2005). The use of 10 mg / liter of ozone completely inactivates 7 log CFU of Salmonella enteritidis from the surface of cherry tomatoes after 15 min, however, the color of the tomatoes is affected (Das et al., 2003).

Because the antimicrobial agents in vapor phase can be effective against bacteria adhered to locations of raw agricultural products not reached by the active agents in aqueous solution, their use in packaged products (in plastic bags) or during the processing of products (in the company) could provide an extra benefit in the control of pathogens. However, this type of steam treatment would not be an optional or practical treatment for the primary producers of lettuce in the field since producers usually sell their product packed in cardboard or wood boxes among other things for ease and to avoid accumulation and humidity what would happen if plastic bags were used. In addition, this would not be a practical treatment to apply in restaurants or homes.

The use of chemical substances as disinfectants of raw vegetables to improve or preserve their innocuousness, is a procedure universally used by producers. However, some of these antimicrobials may be toxic to consumers; This is the case of hypochlorite solutions. Recent reports indicate that hypochlorite in solution can form cancer precursors. In addition, many of the chemical disinfectants, such as solutions based on iodine or colloidal silver, show limited or varied antimicrobial effect in products such as raw vegetables; a similar situation occurs with conservatives for food.

Due to this, disinfectants and preservatives obtained from plants have recently emerged as a viable alternative, since these could have equal or greater antimicrobial potential and with a minimum risk for consumers.

The application of extracts of garlic in fresh fruit against post-harvest diseases has obtained complete control of the brown rot of the peaches caused by Monilinia fructicola (Roller, 2003). Yucel and Karapinar (2005) evaluated the reduction of S. typhimuríum in onions by applying lemon juice, vinegar and their mixtures, observing a respective reduction of 0.87-2.93, 0.66-2.92 and 0.86-3.24 Log CFU / g.

The essential oils from plants are able to inactivate the pathogens of interest in fresh products. Of 96 different types of essential oils examined, only 3 were effective against E. coli 0157: H7 and enteric Salmonella which were of oregano, thyme, and cinnamon. In another study, 16 individual compounds of the most effective oils were tested against E. coli 0157: H7 and Salmonella and the most effective compounds were found to be thymol, cinnamaldehyde, and carvacrol (Friedman et al., 2002). This information was obtained using the oil in the liquid phase. There is limited Information available on the effectiveness of essential oils in the form of vapor. In another study, Muñoz (2003) evaluated the effect of two concentrations of carvacrol and the commercial disinfectant Boradantix © (EVESA, Extractos Vegetales SA) on the survival of L. monocytogenes, P. fluorescens, E. coli, Erwinia caratovora and S. typhimurium in tomato juice. lettuce and carrot. All the study microorganisms were inhibited in both carvacrol concentrations. The bacteria studied showed greater sensitivity to carvacrol than to Boradantix ©. Lin et al., (2000) evaluated the effect of allyl and methyl isocyanate (AITC / MITC) (key components of green mustard) on L. monocytogenes, E. coli 0157: 1-17 and S. montevideo, inoculated on the surface of lettuce and tomato. AITC was more effective against Salmonella and E. coli, achieving 8 Log of reduction with a steam treatment generated of 400 ml of AITC after 4 and 2 days, respectively on lettuce. 8 Log of reduction of S. Montevideo on tomato cuticle with 500 ml of AITC were also achieved.

There have been relatively few studies of the antimicrobial action of essential oils in model food systems and in real foods. However, the efficacy of essential oils in vitro is often much better than in vivo or in situ, ie in foods. Generally, when applying a plant antimicrobial to a food or in vitro, 10 to 100 times more antimicrobial concentration is needed than observed in vivo. For example, the essential oil of peppermint (Mentha piperita) has been shown to inhibit the growth of Salmonella enteritidis and L. monocytogenes in culture media for 2 days at 30 ° C. However, the effect of peppermint essential oil on Greek tzatziki (pH 4.5) and taramasalata (pH 5.0) and on pate (pH 6.8) at 4 ° C and 10 ° C was variable (Roller, 2003). Salmonella enteritidis was eliminated in snacks under all the conditions examined but not when it was inoculated in pâté and kept at 10 ° C. In this same study, L monocytogenes behaved in a similar way, since the microbial count decreased in the appetizers but increased in the paté (Roller, 2003). The growth of E. coli, Salmonella sp., L monocytogenes and Staphylococcus aureus were inhibited by the essential oil of oregano in culture broths. However, when these oils were tested in foods such as eggplant, taramasalata or mayonnaise, reactions such as increased pH, increased temperature and, in the case of emulsions, separation of used oil were observed (Roller, 2003). In another study L monocytogenes and S. typhimurium were inhibited in meat treated with clove and oregano essential oil, respectively. A marked reduction of Aeromonas hydrophila has also been reported in cooked pork that was treated with clove or coriander oils, packaged in vacuum or with air and stored at 2 ° C and 10 ° C. (Roller, 2003).

The differences observed between the studies of antimicrobial effect when oils extracted from plants are applied directly on microorganisms (microorganisms in aqueous suspension) and those in which there is a food or organic matter in between, it is possible that it occurs by the interference with the components of food or organic matter (proteins, fats, sugars, salts). Therefore, it is quite possible that only a proportion of the essential oil added to the food has antibacterial activity. On the other hand, the spatial distribution of the different phases (solid / liquid) in a food and the lack of homogeneity of factors such as pH, aw among others, can play a role in the efficacy. Due to all the above, in different parts of the world there are ongoing studies aimed at the search of alternative antimicrobials (Jongen, 2005). Among the new alternatives of disinfectants has been chosen natural compounds with broad antimicrobial capacity.

It should be noted that the extracts obtained from some plants have shown an antimicrobial effect against strains of multiresistant pathogens. antibiotics, which opens up a whole new field for the development of new antimicrobials for use in humans and animals.

As background of the present application, the antimicrobial effect of around 60 different plants used in herbal medicine has been evaluated (Cruz-Gálvez et al., 2013); where some of these have shown a high antimicrobial power against different pathogenic microorganisms, such as Salmonella or Escherichia coli 0157: H7, among others, as well as against food-deteriorating microorganisms (Pseudomonas aeruginosa, for example), and the plant with the greatest antimicrobial effect has shown to have been the chalices of the flower of Jamaica, being in some cases the antimicrobial effect greater than that of commercial disinfectants based on hypochlorite, iodine, colloidal silver or that of antibiotics such as penicillin.

Different researchers have also reported that the chalices of the flower of Jamaica (Hibiscus sabdariffa L) possess substances with high antimicrobial power (Aziz etal · 1998, Fernández etal., 1996, Kang et al., 2007).

The jamaica is one of the plants in which recently it has been reported the presence of antimicrobial compounds in dehydrated chalices (Aziz et al., 1998, Fernández et al., 1996, Kang et al., 2007). In the chalices of the flower of Jamaica a range of phytochemical compounds have been detected that could be responsible for the observed antimicrobial effect, such as for example polyphenols (Tajkarimi et al., 2010), among them some phenolic acids (Tajkarimi et al. ·, 2010), as well as flavonoids, catechins and epicatechins (Friedman et al., 2002). However, there are no specific studies that show which are the molecules or chemical compounds responsible for the antimicrobial effect observed in the chalices of Jamaica. Different researchers agree that it is necessary to carry out further studies to identify the specific molecules responsible for the antimicrobial effect caused by the chalices of Jamaica in solution.

Scarce are the patent documents that describe extracts of the chalices of the flower of Jamaica (Hibiscus sabdariffa) and their use as material with antimicrobial properties.

For example, patent application JP2002128602 describes its use in an agrochemical composition for protecting plants in seed fields, while application US20100323046 describes the use of a crude extract from Jamaica's calyxes to produce a medicament for treating urinary tract infections caused by Escherichia coli and Candida albicans.

In the patent application KR20080092186 an extract of Jamaica is described which is used to improve the quality of the beef, pork and chicken meat and to increase its storage stability. The extract is prepared by extraction with ethanol and subjected to a cold drying process. The concentration of the extract in the composition is 500 mg / ml and the meat is treated with a preparation of 0.5 to 3.0% (by weight).

On the other hand, in the application US20120015062 are described compositions comprising extract of the plant Agapanthus africanus and compositions comprising this extract plus other extracts of other different plants, such as for example plants of the family Rosa or alfalfa to be used as agents in the biological protection of other plants including their seeds. Although in this patent application document reference is made to the article published by Leksomboon et al. (Kasetsart, Journal Natural Science 35: 392-396, 2001.) where it is mentioned that extracts obtained from various plants (Hibiscus sabdariffa, Psidium guctjava, Punic granatum, Spondias pinnata and Tamarindus indica) have an antimicrobial function, said document does not bring any experimental evidence that involves the extracts of Hibiscus sabdariffa for the same use as the extracts of Agapanthus africanus.

Therefore, it is necessary to have effective antimicrobial protective compositions to prevent and / or combat microbial contamination of food, mainly those that are consumed raw, such as lettuce, in order to preserve and consume them without the risk of acquire diseases caused by their contamination with pathogenic microorganisms.

Until prior to the present invention, it had not been possible to develop effective compositions for efficiently disinfecting and damaging the product as described here, and at the same time allowing to preserve the nutritional properties of fruits and vegetables and not affect, for example the quality of lettuce, with which it is possible with the present invention to obtain innocuous raw lettuces microbiologically.

BRIEF DESCRIPTION OF THE FIGURES Figure 1. The nuclear magnetic resonance spectrum (NMR) of PROTON (1H) of the dry AQUEOUS extract obtained from the chalices of Jamaica that was used in the present invention.

BRIEF DESCRIPTION OF THE INVENTION In accordance with the problems mentioned above, there is a need to provide a more effective formulation to inactivate or remove pathogenic microorganisms from lettuce (Lactuca sativa) even in extreme conditions of treatment, but which do not damage the food sensorially.

The present invention relates to solutions containing phytochemicals present in plant extracts that are used as disinfectants of foods of vegetable and animal origin, for example directed to the disinfection and preservation of foods of vegetable origin, particularly to disinfection and / or preservation of lettuce (Lactuca sativa).

One embodiment of the present invention relates to obtaining a plant preparation comprising aqueous extracts of the chalices of the flower of Jamaica (Hibiscus sabdariffa) which are useful for eliminating pathogens present in food (disinfecting effect) and for delaying deterioration of food or preserve its safety (conservative effect).

Another embodiment of the present invention relates to obtaining extracts derived from plants that are used as disinfectants against pathogenic microorganisms present in food and to delay the deterioration of foods and / or preserve their safety, that is, as preservatives for food. , which constitute an alternative to the use of traditional disinfectants that can become toxic to humans, animals or the environment.

Another embodiment of the present invention relates to the preparation of compositions containing the extract of the chalices of Jamaica (Hibiscus sabdariffa) having a disinfecting and food preservative function together with other compounds having disinfecting properties such as acetic acid, hypochlorite, etc.

Another embodiment of the present invention relates to obtaining extracts obtained from chalices of Jamaica that have a disinfecting or preservative effect when applied to food. One aspect of this modality refers to the application of extracts obtained from chalices of the jamaica plant (Hibiscus sabdariffa) that have a disinfecting or conservative effect when applied to foods of vegetable origin, preferably lettuce.

Another embodiment of the present invention is the development of a method for obtaining the aqueous extract from chalices of Jamaica, an extract that turns out to be useful as a disinfectant and food preservative.

Another embodiment of the present invention is a method of treatment and / or preservation of foods of animal and / or vegetable origin by applying compositions containing extracts of chalices of Jamaica that allow disinfection and their preservation.

The use of extracts of chalices from Jamaica as a disinfectant and / or food preservative is another embodiment described in the present invention.

Compounds from the chalices of Jamaica can be useful in the development of an efficient disinfectant to eliminate pathogenic bacteria present in raw plant foods, such as lettuce. In the present invention although three types of extracts of chalices of jamaica are described, one aqueous, one methanolic and another acetonic, specifically the AQUOSO can be used as a disinfectant and / or food preservative due to its efficiency in the elimination of pathogenic bacteria from raw plant foods such as lettuce.

Unlike other compositions known hitherto for the same purpose, the compositions of the present invention are capable of eliminating the pathogenic bacteria present in raw plant-based foods, such as example lettuce per se, without altering its nutritional properties as well as the quality characteristics of the product. Consequently, the application of the compositions of the present invention in foods of crude vegetable origin, allows their conservation, as well as their effective disinfection, which makes them safe foods for consumption.

DETAILED DESCRIPTION OF THE INVENTION The compositions of the present invention comprise plant extracts with known antimicrobial activity, such as, for example, aqueous and acetone extracts of chalices of the flower of Jamaica, either alone or in combination with other components with proven disinfectant activity, such as, for example, organic acids. which include acetic acid and chlorine compounds that include sodium hypochlorite. In the case of the disinfection of raw plant-based foods such as for example lettuce, the compositions of the invention include a mixture of chalices extracts from the flower of Jamaica as well as acetic acid and sodium hypochlorite and polysorbate, which are usually be very effective in eliminating the microorganisms residing in the vegetable, while at the same time ensuring that their organoleptic and / or nutritional properties are not affected and without being altered, for example the commercial quality of the lettuces.

For purposes of the present invention, the compositions described herein, comprise: a) A methanolic extract derived from plants, which exhibit antimicrobial properties, such as extracts derived from chalices of the flower of Jamaica (Hibiscus sabdariffa), b) An organic acid with disinfectant activity, such as acetic acid, lactic acid, citric acid, peracetic acid, octanoic acid, acid peroxyethanoic acid and 1-hydroxyethylidene-1,1-diphosphonic acid, and mixtures thereof, in a w / w concentration from 0.01% to 10%, preferably from 0.1% to 1%, c) A chlorine compound with disinfectant activity, such as for example sodium hypochlorite, calcium hypochlorite, chlorine dioxide and mixtures thereof in a w / w concentration from 0.001% to 10%, preferably from 0.001% to 0.1%, Y d) A surfactant with emulsifying activity of natural fats or waxes found in tomato, such as polysorbates, Polysorbate 80, Polysorbate 20, C12-C18 alkyl dimethyl betaine (cocobetaine, C10-C16 alkyl dimethylbetaine (laurylbetaine), Sulfobetaine acyl (C10-C14 fatty) amidopropylene (hydroxypropylene), sulfobetaine, Cyclodextrins, B-cyclodextrins and b-Cyclodextrin and mixtures thereof in a w / w concentration from 0.1% to 5%, preferably from 0.5% to 1%.

For purposes of the invention, the compositions are added to the foods to be disinfected and / or preserved by methods known in the art, such as direct application, through sprays, the complete immersion of the fruits and vegetables in the disinfectant solutions. or by means of devices that allow its adequate dispersion in the foods to be treated. The compositions of the invention can be added or contacted with food in an amount of 0.1mL per 1000g of food, preferably 0.1 to 1mL per 100g of food, or be added in larger volumes according to the needs of disinfection of the food. After being applied, the compositions can remain the necessary time until obtaining the desired disinfectant and / or preservation effect in fruits and vegetables. Prior to its consumption, the fruits and vegetables treated with the compositions described herein are simply washed with potable water to eliminate said compositions.

The compositions described herein can be obtained by mixing their components in the desired concentrations, and then storing them at room temperature, so that they are ready to be applied to the food when it is considered necessary.

For purposes of the invention, the compositions described should be in admixture with plant extracts with antimicrobial activity, such as, for example, extracts derived from chalices from Jamaica, which are put in contact with food, for example to foods of crude vegetable origin such as the lettuce, with the purpose of disinfecting them and / or preserving them. In the present invention, describes the disinfectant activity of extracts derived from chalices of Jamaica, in the disinfection and / or preservation of foods, for example to foods of crude vegetable origin, so they can be used directly or forming part of compositions that contain them. In this sense, the extracts derived from the chalices of Jamaica, can be added or put in contact with the foods to be disinfected and / or preserved in a concentration p / p of 0.001% to 10%, preferably from 0.1% to 1%.

The effectiveness of disinfectant and / or preservation in foods of the compositions described herein is such that it inactivates or eliminates bacteria that are pathogenic to the human or food spoilage that may be present in them, while at the same time not affecting the organoleptic properties and / or nutritious food. In the case of fresh foods such as lettuce, the compositions of the invention adequately disinfect the food without affecting its nutritional properties, while at the same time not affecting the organoleptic or quality properties.

The plant extracts of the present invention can be obtained by the following method: a) Place the dried plant in a container under aseptic conditions, add water, in a 1: 9 ratio; preferably 100 g of the dried plant is placed in a container (flask) under aseptic conditions, boil at 90-100 ° C for 15-30 minutes and allow to cool to 20-30 ° C; b) Remove the calyces and recover the aqueous extract; preferably the resulting extract is recovered by pressing on the walls of the flask to remove excess liquid; c) Pass the extract through a sieve and recover the filtered extract; preferably the extract is passed through a No. 200 sieve; d) Remove the water from the extract by rota-evaporation at a temperature of 40 ° C, a rotation of 80 rpm and a vacuum pressure of 72 mbar; e) Recover the dry extract; preferably in a previously sterile contain.

Obtained the extracts these are stored at room temperature until use.

Once obtained the extracts can be used alone, or in combination with other disinfectants to obtain the compositions of the invention, which can be obtained by methods known in the art where it involves the combination of the various elements that form them to form solutions and / or suspensions to be applied subsequently to the food to be disinfected and / or preserved, by methods known in the art.

The present invention constitutes the first report of the use and effectiveness of compositions containing plant extracts with microbial activity, either alone or in combination with other disinfectants, for the disinfection and / or preservation of foods, particularly fruits and vegetables, as example the lettuces. As will be seen below, the compositions of the invention are capable of disinfecting and / or eliminating microorganisms present in lettuce in a very efficient way, with which it is possible to have innocuous lettuces microbiologically and safe for their consumption.

The following examples are included below for the sole purpose of illustrating the present invention, without implying any limitation within its scope.

Example 1. Materials and methods. 1. 1. Plant material.

Dry chalices from Jamaica (Hibiscus sabdariffa) of the Creole variety of Oaxaca were used, while in the case of lettuce (Lactuca sativa) they were used of the Iceberg variety. Lettuces of a size and physiological state or uniform age were obtained. 1. 2. Bacterial strains.

Strains of E. coli 0157: 1-17 (P1C6, isolated from an outbreak of disease), enteroinvasive E. coli (4VC81-5, isolated from clinical case), E. enterotoxigenic E. coli (1620 TL, isolated from clinical case) were used. , Enteropathogenic E. coli (52 GM 291, isolated from clinical case), Salmonella typhimurium (ATCC 14028), Salmonella choleraesuis (ATCC 10708), Listeria monocytogenes (ATCC 19115), Listeria monocytogenes Scott A, Staphylococcus epidermis (ATCC 12228), Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853), Bordetella (ATCC 12741) Shigella sonnei (ATCC 25931) and Shigella flexneri (ATCC 12022), V. cholerae (87151, serotype Inaba isolated from the environment) and Pseudomonas aeruginosa (ATCC 27853 ). Strains of E. coli 0157: H7 and V. cholerae 01 were donated by Dr. Fernández Escartin of the Autonomous University of Querétaro. All the strains were marked with resistance to the antibiotic rifampin (R +) to eliminate the interference of the native microbial flora of the extract (Castro-Rosas and Escartin, 2000). This resistance to the antibiotic was maintained during the entire study. The strains were maintained at 4 - 7 ° C on blood-based agar (ABS, Merck®, Germany) with biweekly transfers, activating in tripticasein soy broth (CST, Bioxon®, Mexico) with incubation at 35 ° C / 24h. 1. 3. Obtaining aqueous extract from the chalices of Jamaica.

Under aseptic conditions 100 g of chalices from Jamaica were placed in an Erlenmcyer flask, to which 900 mL of distilled water was added, bringing the mixture to boiling for 20 minutes. Once the treatment was finished, it was allowed to cool to room temperature. The calyxes were removed from the extract (after pressure on the walls of the flask to remove excess liquid from it) and then the extract was passed through a No. 200 sieve (MONTIMAX) to remove particles. Finally, all the water was removed from the extract by a broken evaporation using a broken evaporator (Buchi R-205) using the following conditions: temperature of 40 ° C of the tub, rotation of 80 rpm and vacuum pressure of 72 mbar. The dried extract was recovered in a sterile bottle and stored at room temperature until use. 1. 4. Obtaining methanolic and acetonic extract from the chalices of Jamaica.

Under aseptic conditions 100 g of chalices from Jamaica were placed in an Erlenmeyer flask, to which 900 mL of methanol or acetone was added and stored for 7 days at room temperature. Once the treatment was finished, the calyces were removed from the extract (after pressing the walls of the flask to remove excess liquid from it) and then the extract was passed through a No. 200 sieve (MONTIMAX) to remove particles. Finally, all the methanol or acetone was removed from the extract by a broken evaporation using a broken evaporator (Buchi R-205) using the following conditions: temperature of 40 ° C of the tub, rotation of 80 rpm and vacuum pressure of 72 mbar. Dry extracts (methanolic or acetonic) recovered separately in a sterile bottle and stored at room temperature until use. 1. 5. Determination of the antimicrobial activity of the aqueous, methanolic and acetonic extracts of the chalices of Jamaica in culture medium (in vi tro studies). 1. 5.1. Preparation of the inoculum of the strains.

Test tubes with cultures of 24 h in CST of each R + strain, were centrifuged at 3500 rpm for 20 min. Subsequently the supernatant was discarded; the cell pack was resuspended by adding 3 ml_ of sterile isotonic saline and vortexing for 10 s. The above procedure was repeated twice more. Subsequently, the concentration of each strain was approximately 1x10 9 CFU / ml_. Finally, each strain was diluted decimally in isotonic saline only once. 1. 5.2. Preparation of the solutions of the extracts.

From the dry extracts, aqueous solutions were prepared using sterile distilled water or a solution of Polysorbate 80: water in a 20:80 ratio. The aqueous and methanolic extracts were solubilized in distilled water while the acetonic extracts were solubilized in the solution of Polysorbate 80: water. To the water or polysorbate 80: water, the dry extracts were added in a 1:10 ratio (water: extract) separately and they will be deposited in sterile bottles. 1. 5.3 Antimicrobial effect of the extracts in culture medium.

Separately, 100 mL of the first dilution of the cultures of the pathogens were inoculated on boxes of AST supplemented with 10 mg / L of the antibiotic rifampicin, the inoculum was distributed over the entire surface of the agar by the surface extension technique. On the inoculated boxes, for separated, aliquots of 10 mL of the solution of the extracts (aqueous, methanolic or acetonic) were placed. Four repetitions were performed for each treatment. After the extract or fractions were absorbed by the agar, the culture boxes were incubated at 35 ± 1 ° C, for 24 h. Finally, the diameter of each of the inhibition halos formed on the surface of the inoculated medium was measured. 1. 6. Evaluation of the antimicrobial effect of aqueous extracts, methanolic, acetonic, acetic acid, hypochlorite and specific formulations in the reduction of Salmonella and E. coli 0157: H7 in contaminated lettuce. 1. 6.1. Preparation of disinfectant solutions.

The solutions of calyx extracts from Jamaica as well as the mixtures containing extracts, acetic acid and hypochlorite were prepared at the concentrations, proportions or mixtures described in Table 1. For example, to prepare 100 ml of a solution containing methanolic extract of 1% Jamaica chalices, 0.1% acetic acid and 100 mg / L of hypochlorite: to 100 mL of distilled water was added 1 g of dry methanolic extract of chalices from Jamaica, plus 1 ml of a solution of 10% acetic acid % and 0.2 ml of a 5% hypochlorite solution. To these solutions, the surfactant polysorbate 80 (also known as tween 80) is added or not to the ratio described in table 1. 1. 6.2. Strains For these studies we worked with 7 serotypes of Salmonella: (3 typhimurium [ATCC 14028, one isolated from tomato, J1, and another from alfalfa seed, GA1], Salmonella choleraesuis [ATCC 10708], typhi, gaminara, and montevideo) and 3 of E. coli 0157: H7 (two isolated in our laboratory from raw meat [P1C6 and M5C8] and another isolated from an outbreak caused by meat consumption in the United States of America [E09]). All strains were marked with resistance to the antibiotic rifampicin (R +) to eliminate the interference of the native microbial flora of the extract (Castro and Escartín, 2000).

Table 1. Treatments to which the leaves of lettuce contaminated with mixtures of Salmonella strains or strains of E. coli 0157 were subjected separately: H7 Treatments 1 Without treatment (control) 2 aqueous extract 1% 3 Acetone extract 1% 4 Methanolic extract 1% 5 Sodium hypochlorite 50 ppm 6 Sodium hypochlorite 100 ppm 7 Acetic acid 0 1% 8 Acetic acid 0.5% 9 Aqueous extract 1% + acetic acid 0.1% 10 Aqueous extract 1% + acetic acid 0.5% 11 Acetone extract 1% + acetic acid 0.1% 12 Acetone extract 1% + acetic acid 0.5% 13 Methanolic extract 1% + acetic acid 0.1% 14 Methanolic extract 1% + acetic acid 0.5% 15 Aqueous extract 1% + acetic acid 0.1% + sodium hypochlorite 50 ppm 16 Aqueous extract 1% + acetic acid 0.5% + sodium hypochlorite 50 ppm 17 Water extract 1% + acetic acid 0.1% + sodium hypochlorite 100 ppm 18 Aqueous extract 1% + acetic acid 0.5% + sodium hypochlorite 100 ppm 19 Acetone extract 1% + acetic acid 0.1% + sodium hypochlorite 50 ppm 20 Acetone extract 1% + acetic acid 0.5% + sodium hypochlorite 50 ppm 21 Acetone extract 1% + acetic acid 0.1% + sodium hypochlorite 100 ppm 22 Acetone extract 1% + acetic acid 0.5% + sodium hypochlorite 100 ppm 23 Methanolic extract 1% + acetic acid 0.1% + sodium hypochlorite 50 ppm 24 Methanolic extract 1% + acetic acid 0.5% + sodium hypochlorite 50 ppm 25 Methanolic extract 1% + acetic acid 0.1% + sodium hypochlorite 100 ppm 26 1% methanolic extract + 0.5% acetic acid + 100 ppm sodium hypochlorite 27 Aqueous extract 1% + acetic acid 0.1% + sodium hypochlorite 50 ppm + Polysorbate 802% 28 Aqueous extract 1% + acetic acid 0.5% + sodium hypochlorite 50 ppm + Polysorbate 802% 29 Aqueous extract 1% + acetic acid 0.1% + sodium hypochlorite 100 ppm + Polysorbate 802% 30 Aqueous extract 1% + acetic acid 0.5% + sodium hypochlorite 100 ppm + Polysorbate 802% 31 Acetone extract 1% + acetic acid 0.1% + sodium hypochlorite 50 ppm + Polysorbate 802% 32 Acetone extract 1% + acetic acid 0.5% + sodium hypochlorite 50 ppm + Polysorbate 802% 33 Acetone extract 1% + acetic acid 0.1% + sodium hypochlorite 100 ppm + Polysorbate 802% 34 Acetone extract 1% + acetic acid 0.5% + sodium hypochlorite 100 ppm + Polysorbate 802% 35 Methanolic extract1% + acetic acid 0.1% + sodium hypochlorite 50 ppm + Polysorbate 802% 36 Methanolic extract1% + acetic acid 0.5% + sodium hypochlorite 50 ppm + Polysorbate 802% 37 Methanolic extract1% + acetic acid 0.1% + sodium hypochlorite 100 ppm + Polysorbate 802% 38 Methanolic extract 1% + acetic acid 0.5% + sodium hypochlorite 100 ppm + Polysorbate 802% For the preparation of the solutions, the following was used: A) the dry extract of the chalices of Jamaica in the previous section, B) Sodium hypochlorite solution with 5% free hypochlorite, C) 10% glacial acetic acid, d) Sorbitan Polyoxyethylene Monooleate, or polysorbate 80 ( Pollsorbate 80), d) Sterile distilled water at pH 6 1. 6.3. Preparation of the inoculum of the strains.

Test tubes with cultures of 24 h in CST of each R + strain, were centrifuged at 3500 rpm for 20 min. Subsequently the supernatant was discarded; the cell pack was resuspended by adding 3 mL of sterile isotonic saline and vortexed for 10 s. The above procedure was repeated twice more. The resulting concentration of each strain was approximately 1x10 9 CFU / mL. One milliliter of each Salmonella strain was mixed in an empty test tube to have a mixture of the 7 Salmonella strains examined. The same was done with strains of E. coli 0157: H7, to have a mixture of the three strains of E. coli 0157: H7. 1. 6.4. Lettuce inoculation Lettuces of the Iceberg varieties were used; the lettuces were obtained from a local producer. Prior to inoculation, the leaves were separated from the lettuces and gently wiped with a clean cloth to remove dust particles. Whole lettuce leaves of a uniform or similar size were used and showed no visible damage. Separately, the lettuce leaves were individually inoculated by placing in 10 different central parts of each leaf 10 mL of a suspension of each type of pathogenic bacteria mixture (Salmonella or E. coli 0157: 1-17) containing approximately 1 x 107 CFU, the inoculated leaves were placed in a tray and introduced in a bioclimatic bell for two hours at a relative humidity of 90 ± 1% and 26.5 ± 1 ° C. The purpose of this treatment was to cause the adherence or infiltration of the cells of the pathogenic bacteria studied to simulate natural or common contamination conditions. 1. 6.5. Disinfection treatment of lettuce leaves.

After two hours in the bioclimatic chamber, each leaf was washed separately to eliminate the microorganisms that did not adhere, the washing consisted of immersing and stirring the inoculated parts of the lettuce in water distilled by 10 S; the washed part was allowed to drain at room temperature until total dryness and then, separately, the inoculated part of the lettuces was immersed for 10 min in the different disinfectant solutions indicated in Table 1. A treatment only with distilled water served as a positive control . 1. 6.6. Counting microorganisms surviving treatments After the treatment, the lettuce leaves were removed from the disinfectant solution and to remove the remaining disinfectant the inoculated part was submerged in distilled water for 10 s, then the inoculated parts were cut with the help of a sterile scalpel, the portions of each lettuce they were placed together in a plastic bag and 10 ml of peptone diluent was added. Subsequently, the materials were shaken manually by pressing and rubbing vigorously the inoculated part and the whole portion of lettuce inoculated from the outside of the bag for 2 minutes. After this time, each bag was counted by the plate pouring technique using agar for standard methods (Bioxon, Mexico) added with 100 mg / L of Rifampicin (Sigma, Mexico), the boxes were incubated at 35 ° C / 24-48 h. This procedure was performed in duplicate for each replicate. Each treatment was carried out in quintuplicate. 1. 6.7. Statistic analysis The results obtained were analyzed statistically with a one-way analysis of variance (ANOVA) comparing the means with the Tukey test, with a level of significance of 0.05. 1. 7. Nuclear Magnetic Resonance (NMR) of the extracts The proton NMR spectrum (1H) of both the dried aqueous extract obtained from the chalices of Jamaica was determined. The extracts were solubilized in deuterated water. The NMR spectra were obtained using a nuclear magnetic resonance spectrometer (Varian NMR, 400 MHz).

NMR spectroscopy studies the atomic nuclei. This spectroscopic technique can be used only to study atomic nuclei with an odd number of protons or neutrons (or both), to determine the structures of the organic compounds. This situation occurs in the atoms of 1H I3Q i9p ^ 3ip ste 0 nijC | eos are magnetically active, that is to say they possess spin, just like electrons, since the nuclei have positive charge and have a rotation movement on an axis that makes them behave as if they were small magnets. The NMR spectrometer detects these signals and registers them as a graph of frequencies versus intensity, which is the so-called NMR spectrum.

Example 2. Antimicrobial effect of the extracts of the chalices of Jamaica.

The three types of extracts (aqueous, methanolic and acetonic) showed a marked antimicrobial effect (Table 2). All the microorganisms tested were inhibited from the first moments of contact. However, the methanolic extract showed the highest antimicrobial activity (Table 2). And the one that showed less effect was the aqueous extract.

The inhibitory effect observed suggests the presence of antimicrobial substances in the extracts. This effect can cause lethal damage to the cell or only cause a sublethal effect or cellular stress (Busta, 1976). Different components of the plant could be responsible for this antimicrobial effect. It is possible that the chalices of Jamaica contain different antimicrobials; that is, the antimicrobial effect may be due to the effect of different molecules with antimicrobial activity, this observation is based on the fact that the extracts were obtained with three solvents of different polarity, and the three types of extracts showed antimicrobial activity.

Table 2. Antimicrobial effect of the aqueous extract of Jamaica diluted 1:10 and that of a solution of penicillin (control) on different microorganisms * (mm) Example 3. Potential disinfectant of the extracts alone or in mixtures with acetic acid, sodium hypochlorite and / or Polysorbate 80.

It was found that all the treatments had an antimicrobial effect with respect to the control (Tables 3). However only 3 combinations (28, 29 and 30) were 100 percent effective (Tables 3) to disinfect the lettuce. It was with the combination in which the aqueous extract of the chalices of Jamaica was included. For some reason, already when applying the aqueous extracts in combination with the other components of treatments 28, 29 and 30, directly on the lettuce, these extracts showed greater effect than the methanolic and acetonic. This suggests that in the methanolic extract specific substances are present that are not present in the other extracts or in the other extracts if they are present but in much lower concentration in such a way that they do not influence the antimicrobial effect.

Table 3. Concentration of E. Coti 0157: 1-17 and S.T phimurium in lettuce at the beginning and after different treatment E. cotí 0157: H7 Salmonella Treatment Number Number Number Number Initial Final Initial Final Without treatment (control) 4.80 ± 0.201 * 4.60 ± 0.30 5.00 ± 0.30 4.80 ± 0.20 2 Water extract 1% 4.80 ± 0.20 3.20 ± 0.30 5.00 ± 0.30 3.00 ± 0.20 3 Acetone extract 1% 4.80 ± 0.20 3.00 ± 0.30 5.00 ± 0.30 3.00 ± 0.20 4 Methanolic extract 1% 4.80 ± 0.20 3.10 ± 0.30 5.00 ± 0.30 3.10 ± 0.20 5 Sodium hypochlorite 50 ppm 4.80 ± 0.20 3.20 ± 0.30 5.00 ± 0.30 3.60 ± 0.20 6 Sodium hypochlorite 100 ppm 4.80 ± 0.20 2.80 ± 0.40 5.00 ± 0.30 3.30 ± 0.20 7 Acetic acid 0.1% 4.80 ± 0.20 3.20 ± 0.30 5.00 ± 0.30 3.20 ± 0.30 8 Acetic acid 05% 4.80 ± 0.20 3.00 ± 0.20 5.00 ± 0.30 3.00 ± 0.30 9 Aqueous extract 1% + acetic acid 0.1% 4.80 ± 0.20 2.80 ± 0.30 5.00 ± 0.30 2.90 ± 0.40 10 Aqueous extract 1% + acetic acid 0.5% 4.80 ± 0.20 2.30 ± 0.20 5.00 ± 0.30 2.20 ± 0.40 11 Acetone extract 1% + acetic acid 0.1% 4.80 ± 0.20 2.60 ± 0.20 5.00 ± 0.30 2.60 ± 0.20 12 Acetone extract 1% + acetic acid 0.5% 4.80 ± 0.20 2.20 ± 0.30 5.00 ± 0.30 2.20 ± 0.20 13 Methanolic extract 1% + acetic acid 0.1% 4.80 ± 0.20 2.50 ± 0.30 5.00 ± 0.30 2.50 ± 0.30 14 Methanolic extract 1% + acetic acid 0.5% 4.80 ± 0.20 2.20 ± 0.20 5.00 ± 0.30 2.20 ± 0.30 15 Water extract 1% + acetic acid 0.1% + sodium hypochlorite 50 ppm 4.80 ± 0.20 2.20 ± 0.30 5.00 ± 0.30 2.00 ± 0.20 16 Aqueous extract 1% + acetic acid 0.5% + sodium hypochlorite 50 ppm 4.80 ± 0.20 2.10 ± 0.30 5.00 ± 0.30 1.80 ± 0.20 17 Aqueous extract 1% + acetic acid 0.1% + sodium hypochlorite 100 ppm 4.80 ± 0.20 2.00 ± 0.20 5.00 ± 0.30 1.90 ± 0.30 18 Aqueous extract 1% + acetic acid 0.5% + sodium hypochlorite 100 ppm 4.80 ± 0.20 1.9D ± 0.30 5.00 ± 0.30 2.00 ± 0.20 19 Acetone extract 1% + acetic acid 0.1% + sodium hypochlorite 50 ppm 4.80 ± 0.20 1.80 ± 0.30 5.00 ± 0.30 2.00 ± 0.30 20 Acetone extract 1% + acetic acid 0.5% + sodium hypochlorite 50 ppm 4.80 ± 0.20 1.90 ± 0.30 5.00 ± 0.30 1.90 ± 0.30 o 21 Acetone extract 1% + acetic acid 0.1% + sodium hypochlorite 100 ppm 4.80 ± 0.20 1.40 ± 0.30 5.00 ± 0.30 1.60 ± 0.30 22 Acetone extract 1% + acetic acid 0.5% + sodium hypochlorite 100 ppm 4.80 ± 0.20 1.20 ± 0.30 5.00 ± 0.30 2.20 ± 0.30 23 Methanolic extract 1% + acetic acid 0.1% + sodium hypochlorite 50 ppm 4.80 ± 0.20 1.80 ± 0.30 5.00 ± 0.30 2.00 ± 0.30 24 Methanolic extract 1% + acetic acid 0.5% + sodium hypochlorite 50 ppm 4.80 ± 0.20 1.90 ± 0.30 5.00 ± 0.30 1.80 ± 0.20 25 Methanolic extract 1% + acetic acid 0.1% + sodium hypochlorite 100 ppm 4.80 ± 0.20 1.20 ± 0.30 5.00 ± 0.30 1.40 ± 0.20 26 Methanolic extract 1% + acetic acid 0.5% + sodium hypochlorite 100 ppm 4.80 ± 0.20 1.40 ± 0.40 5.00 ± 0.30 1.20 ± 0.20 27 Aqueous extract 1% + acetic acid 0.1% + sodium hypochlorite 50 ppm + Polysorbate 802% 4.80 ± 0.20 1.20 ± 0.40 5.00 ± 0.30 1.10 ± 0.30 28 Aqueous extract 1% + acetic acid 0.5% + sodium hypochlorite 50 ppm + Polysorbate 802% 4.80 ± 0.20 0.00 S.00 ± 0.30 0.00 29 Aqueous extract 1% + acetic acid 0.1% + hypochlorite deodium 100 ppm + Polysorbate 802% 4.80 ± 0.20 0.00 5.00 ± 0.30 0.00 30 Aqueous extract 1% + acetic acid 0.5% + sodium hypochlorite 100 ppm + Polysorbate 802% 4.80 ± 0.20 0.00 5.00 ± 0.30 0.00 31 Acetone extract 1% + acetic acid 0.1% + sodium hypochlorite 50 ppm + Polysorbate 802% 4.80 ± 0.20 1.70 ± 0.20 5.00 ± 0.30 1.70 ± 0.30 32 Acetone extract 1% + acetic acid 0.5% + sodium hypochlorite 50 ppm + Polysorbate 802% 4.80 ± 0.20 1.50 ± 0.20 5.00 ± 0.30 1.10 ± 0.30 33 Acetone extract 1% + acetic acid 0.1% + sodium hypochlorite 100 ppm + Polysorbate 802% 4.80 ± 0.20 1.70 ± 0.20 5.00 ± 0.30 1.80 ± 0.20 34 Acetone extract 1% + acetic acid 0.5% + sodium hypochlorite 100 ppm + Polysorbate 802% 4.80 ± 0.20 1.60 ± 0.20 5.00 ± 0.30 1.70 ± 0.20 35 Extract methanol glycol% + acetic acid 0.1% + sodium hypochlorite 50 ppm + Polysorbate 802% 4.80 ± 0.20 1.50 ± 0.20 4.00 ± 0.30 1.80 ± 0.30 36 Methanol extract% + acetic acid 0.5% + sodium hypochlorite 50 ppm + Polysorbate 802% 4.80 ± 0.20 1.40 ± 0.20 4.00 ± 0.30 1.20 ± 0.20 37 Extract methanol glycol% + acetic acid 0.1% + sodium hypochlorite 100 ppm + Polysorbate 802% 4.80 ± 0.20 1.30 ± 0.20 4.00 ± 0.30 1.40 ± 0.20 38 Methanol +% extract + acetic acid 0.5% + sodium hypochlorite 100 ppm + Polysorbate 802% 4.80 ± 0.20 1.20 ± 0.20 4.00 ± 0.30 1.10 ± 0.20 1 Colony Forming Unit / inoculated portion, * Average number of studies per quintuplicate, ±: standard deviation In Table 3, it is observed that only 3 combinations managed to eliminate the concentration of mixtures of each pathogen at non-detectable levels: treatments 28, 29, 30 reduced the concentration of both types of pathogens by 5 logio (Tables 3) In the present invention, 3 specific combinations (treatment 28, 29, 30) of three antimicrobials and a surfactant (polysorbate), achieved the total elimination of the pathogenic microorganisms inoculated on the leaves d elechuga entero; this is an example of what is now known as multiple barrier treatment. Multiple barriers are the combination of antimicrobial treatments that enhance the overall antimicrobial effect, which results in stable, safe and safe foods.

It should be noted the possible enhancing role of polysorbate 80 in the observed antimicrobial effect, since being a surfactant it is possible that it has favored the emulsification of the natural wax of lettuce leaves which could increase the effect of the disinfectant solution by eliminating or decrease the protective effect that the wax would be providing to the microorganisms inoculated on the leaves of lettuce Therefore, the compositions of the present invention are an excellent alternative for the disinfection and / or preservation of foods, for example foods of crude vegetable origin, without altering their nutritional properties. In this sense, the compositions described here allow the disinfection or effective inactivation of pathogenic microorganisms of raw plant foods, preferably lettuces, allowing the safe consumption of such products.

Example 4. Nuclear magnetic resonance (NMR) spectrum obtained from the acetonic extract.

The NMR spectrum obtained from the dry aqueous extract of the chalices of Jamaica is presented in Figure 1. In the spectrum several characteristic peaks of the extract that we use in the formulations are observed. This spectrum characterizes the aqueous extract used in the antimicrobial formulations of Table 3.

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Claims (28)

CLAIMS Having sufficiently described my invention, I consider as a novelty and therefore claim as my exclusive property, what is contained in the following clauses:

1. A solution with antimicrobial activity to disinfect and / or preserve lettuce (Lactuca sativa), characterized in that it comprises: a) Water extract of chalices from Jamaica (Hibiscus sabdariffa) b) Acetic acid; c) Sodium hypochlorite; d) Sorbitan polyoxyethylene mono-oleate, or polysorbate 80 (Polysorbate 80)

2. The solution with antimicrobial activity according to claim 1, characterized in that the a) aqueous extract of chalices of Jamaica (Hibiscus sabdariffa) is present in a concentration between 0.01% to 10%.

3. The solution with antimicrobial activity according to claim 1, characterized in that b) acetic acid is present in a concentration between 0.01 to 10%.

4. The solution with antimicrobial activity according to claim 1, characterized in that c) Sodium hypochlorite is present in a concentration between 10 to 1000 ppm.

5. The solution with antimicrobial activity according to claim 1, characterized in that the d) Polyoxyethylene Sorbitan monooleate, or polysorbate 80 is present in a concentration between 0.1 to 10%.

6. The solution with antimicrobial activity according to claim 1, characterized in that the e) aqueous extract of chalices from Jamaica (Hibiscus sabdariffa) presents a nuclear magnetic resonance spectrum (NMR) as seen in Figure 1.

7. The solution of claim 1, characterized in that it has a presentation as an aqueous formulation.

8. The solution of claim 1 according to the preceding claims, characterized in that one or several parts of Jamaica (Hibiscus sabdariffa) can be used to obtain the extract.

9. The solution of claim 1 according to the preceding claims, wherein the part of the Jamaican plant that is employed are the chalices.

10. The solution defined in the preceding claims, characterized by a nuclear magnetic resonance spectrum (NMR) of the aqueous extract obtained from the chalices of the Jamaica (Hibiscus sabdariffa) (Figure 1).

11. The solution of claim 1 according to the preceding claims, characterized in that it is useful as a disinfectant and preservative of foods of vegetable and animal origin.

12. The solution of claim 1 according to the preceding claims, characterized in that the aqueous formulation is useful as a disinfectant and preservative of fruits and vegetables, especially lettuce.

13. The solution of claim 1 according to the preceding claims, characterized in that the main varieties of lettuce (Lactuca sativa) on which it acts as a disinfectant are selected from Orejona, Romana, Iceberg, Boston, Italian, Cos, Baby, Butterhead, Cutting, Stalk, Latin.

14. A method for the disinfection and / or preservation of lettuce (Lactuca sativa), characterized in that it comprises applying to the lettuce the solution defined in the previous claims.

15. A plant extract with antimicrobial activity to disinfect and / or preserve lettuce (Lactuca sativa), characterized in that it is obtained through the following stages: a) Place the dried plant in a container under aseptic conditions, add water, boil for 20 minutes and allow to cool to 22 ° ± 2 ° C, b) Pass the extract through a sieve and remove the water from the extract, and c) Recover the dry extract.

16. The extract of claim 15, characterized in that it is obtained with water.

17. The extract according to claim 15, wherein one or several parts of the plant can be used to obtain the extract.

18. The extract of claim 15, characterized in that the plant is the plant of Jamaica (Hibiscus sabdariffa).

19. The extract of claim 15 according to the preceding claims, characterized in that the extract is obtained from the chalices of the Jamaica.

20. The extract of claim 15 according to the preceding claims, characterized in that it has a nuclear magnetic resonance spectrum (NMR) as seen in Figure 1.

21. The extract of claim 15 according to the preceding claims, characterized in that it is useful as a disinfectant and preservative of foods of animal and vegetable origin.

22. The extract of claim 15 according to the preceding claims, characterized in that it is useful as a disinfectant and preservative of fruits and vegetables, preferably lettuce.

23. The extract of claim 15 according to the preceding claims, characterized in that the main varieties of lettuce (Lactuca sativa) on which it acts as a disinfectant are selected from Orejona, Romana, Iceberg, Boston, Italian, Cos, Baby, Butterhead, Cutting , Stalk, Latin.

24. A method for the disinfection and / or preservation of lettuce (Lactuca sativa), characterized in that it comprises applying to the lettuce the extract defined in claims 15 to 23.

25. A method for obtaining a plant extract with antimicrobial activity for disinfecting and / or preserving lettuce (Lactuca sativa), characterized in that it comprises the following stages: a) Place the dried plant in a container under aseptic conditions, add water, boil for 20 minutes and allow to cool to 22 ° ± 2 ° C, b) Pass the extract through a sieve and remove the water from the extract, and c) Recover the dry extract.

26. The method for obtaining the plant extract of claim 25, characterized in that the extract can have a solid or liquid presentation.

27. A method for the preparation of a solution with antimicrobial activity for disinfecting and / or preserving lettuce (Lactuca sativa), characterized by understanding the steps of: a) Place dried Jamaica (Hibiscus sabdariffa) in a container under aseptic conditions, add water, boil for 20 minutes and allow to cool to 22 ° ± 2 ° C, b) Pass the extract through a sieve and remove the water from the extract and, c) Recover the dry extract, d) Prepare the aqueous solution in a container containing: water, dry aqueous extract of the plant, acetic acid, sodium hypochlorite and Polyoxyethylene Sorbitan monooleate or polysorbate 80,

28. The method according to claim 27 wherein the part of the Jamaican plant that is employed are the chalices.