In agreement with the current trend of giving value to natural and renewable resources, the use of natural antimicrobial compounds, particularly in food and biomedical applications, becomes very frequent. The direct addition of natural compounds to food is the most common method of application, using antibacterial products to control e-coli, even if numerous efforts have been made to find alternative solutions to the aim of avoiding undesirable inactivation.
Dipping, spraying, and coating treatment of food with active solutions are currently applied to product prior to packaging as valid options.
The aim of the current work is to give an overview on the use of natural compounds in food sector. In particular, the review will gather numerous case-studies of meat, using antibacterial products to control e-coli, fish, dairy products, minimally processed fruit and vegetables, and cereal-based products where these compounds found application.
Many food products are perishable by nature and require protection from spoilage during their preparation, storage, and distribution to give them desired shelf life. The demand for minimally processed, easily prepared, and ready-to-eat fresh food products, globalization of food trade, and distribution from centralized processing pose major challenges for food safety and quality.
Food products can be subjected to contamination by bacteria and fungi. Many of these microorganisms can cause undesirable reactions that deteriorate flavor, odor, color, sensory, and textural properties of foods. Microbial growth is a major concern because some microorganisms can potentially cause food-borne illness.
In packaged foods, growth and survival of common spoilage and pathogenic microorganisms such as Listeria monocytogenes, Escherichia coli O, Salmonella, Staphylococcus aureus, Bacillus cereus, Campylobacter, Clostridium perfringens, Aspergillus nigerand Saccharomyces cerevisiae are affected by a variety of intrinsic factors, such as pH and presence of oxygen or by extrinsic factors associated with storage conditions, including temperature, time, and vancouver asthma and allergy humidity Singh et al.
To prevent growth of spoilage and pathogenic microorganisms in foods, several preservation techniques, using antibacterial products to control e-coli as heat treatment, salting, acidification, and drying have been used in the food industry Davidson and Taylor, ; Using antibacterial products to control e-coli, Numerous efforts are conducted to find natural alternatives to prevent bacterial and fungal growth in foods. In recent years, because of the great consumer awareness and concern regarding synthetic chemical additives, foods preserved with natural additives have become very popular.
To inhibit growth of undesirable microorganisms in food, the antimicrobials can be directly added into the product formulation, coated on its surface or incorporated into the packaging material. Main natural compounds are essential oils derived from plants e.
In this context, plant essential using antibacterial products to control e-coli are gaining a wide interest in food industry for their potential as decontaminating agents, as they are Generally Recognized as Safe GRAS.
The active components are commonly found in the essential oil fractions and it is well established that most of them have a wide spectrum of antimicrobial activity, against food-borne pathogens and spoilage bacteria Gutierrez et al. Usually, the compounds with phenolic groups as oils of clove, oregano, rosemary, thyme, sage, and vanillin are the most effective Skandamis et al.
They are more inhibitory against Gram-positive than Gram-negative bacteria Mangena and Muyima, using antibacterial products to control e-coli, ; Marino et al. Allyl-isothiocyanate is the major antimicrobial component of mustard and horseradish oil.
It has been found to be more effective against Gram-negative bacteria with less or no effect on lactic acid bacteria. Although its antimicrobial activity varies widely Delaquis and Mazza,the volatile compound particularly inhibits E. The use of bacteriocin-producing lactic acid bacteria or their more or less purified bacteriocins has been also receiving increased interest.
Bacteriocins are small bacterial peptides that show strong antimicrobial activity against closely related bacteria. Nisin is a polypeptide produced by Lactococcus lactis spp. It has been approved as a food additive with GRAS status in over 50 countries worldwide. It has a relatively broad spectrum of activity against various lactic acid bacteria and other Gram-positive bacteria.
Moreover, it is particularly effective against heat-resistant bacterial spores of Clostridium botulinum and against food-borne pathogens such as L. Use of nisin in conjunction with ethylenediamine tetra-acetic acid EDTA may increase the effectiveness. The enzymes represent another group of natural compounds that found application in food as valid preservatives. Commercially, lysozyme has been used primarily to prevent late blowing in semi-hard cheeses, caused by Clostridium tyrobutyricum.
It is well known that lysozyme is bactericidal against Gram-positive bacteria, whereas it is essentially ineffective against Gram-negative bacteria, owing to the presence of a lipopolysaccharide layer in the outer membrane. Organic acids and their salts are widely used as chemical antimicrobial agents because their efficacy is generally well understood and cost effective.
The most effective organic compounds are acetic, lactic, propionic, sorbic, and benzoic acid. Their antimicrobial effect is based on the increase in proton concentration thereby lowering the external pH. Organic acids may affect the integrity of microbial cell membrane or cell macromolecules or interfere with nutrient transport and energy metabolism, causing bactericidal effect Ricke, Production of organic acids had been possible before the discovery of microorganisms, with lactic acid first being commercially produced by fermentation inbut the majority of the organic acids produced were being chemically extracted or synthesized from other chemicals.
Mixtures of acids could exert a wider antimicrobial activity than a single organic acid Theron et al. Among the natural antimicrobials, chitosan also received considerable interest for commercial applications.
It has been used in medical, food, agricultural, and chemical industry, mainly due to its high biodegradability and antimicrobial properties. The biological activity of chitosan depends on its molecular weight, degree of deacetylation and derivatisation, such as degree of substitution, length, and position of a substitute in glucosamine units of chitosan, pH of chitosan solution and the target organisms No et al.
It is commercially produced from crab and shrimp shell wastes, with different deacetylation grades and molecular weights and, hence, using antibacterial products to control e-coli, using antibacterial products to control e-coli possess different functional properties, like emulsification ability, dye binding, and gelation.
Chitosan has also been documented to possess a film-forming property for use as edible film or coating, to decrease water vapor and oxygen transmission, diminish respiration rate and increase shelf life of fruit Jiang and Li, This review focuses on the use of natural compounds to control microbiological and physicochemical shelf life of main food categories, such as meat, fish, dairy products, minimally processed fruit and vegetables and cereal-based goods.
The information is mostly based on case-studies dealing with application of active compounds to prevent microbial proliferation occurring in packaged food during storage. Minimally processed products are one of the major growing segments in food retail establishments. However, fresh-cut fruit and vegetables are widely studied because of the difficulties in preserving their fresh-like quality during prolonged periods.
The goal of fresh-cut products is to deliver convenience and high quality. Dipping, impregnation, coating, and spraying are the different ways of applications of active agents to fresh-cut fruit and vegetables but among them, the most recent results on the application of active compounds to ready-to-eat fruit and vegetables deal with coating systems. In the follow, some relevant examples are reported.
Relevant examples of natural active agents applied to minimally processed products. Malic acid in combination with various stabilizing compounds was used by Raybaudi-Massilia et al.
As reported by Bico et al. The antimicrobial effects of propionic, acetic, lactic, malic, and citric acid against E. The active compounds were incorporated into an alginate-based edible coating.
Melon pieces were inoculated with a S. The incorporation of essential oils or their active compounds into the edible coating prolonged the microbiological shelf-life by more than 21 days.
Both citral 25— ppm and citron essential oil, ppm were able to prolong the microbial shelf-life. The same essential oil showed a strong inhibition against L. Generally, when applying bioactive coatings containing essential oils to fruits and vegetables, one of the limiting factors is the impact of such components on the sensory characteristics of the coated products, mainly due to the great using antibacterial products to control e-coli of volatile compounds which mask the natural flavor of fruits and vegetables.
The use of compatible essential oil-foodstuff could also be a good alternative. Ethanol combined with methyl jasmonate was more effective in suppressing microbial proliferation than each single compound. In addition, this combination preserved firmness and color better than the other antimicrobial using antibacterial products to control e-coli. Moreover, methyl jasmonate let keep higher content of lycopene, ascorbic acid and phenolic compounds Ayala-Zavala et al.
All the other studied antimicrobial coatings significantly inhibited growth of psychrophilic aerobes, using antibacterial products to control e-coli, yeasts, and moulds.
The antimicrobial effect of essential oils against L. Grape-fruit seed extract was used as antimicrobial compound into a coating of sodium alginate to prolong the shelf-life of minimally processed kiwifruits.
The combination of an active compound to an alginate-based coating delayed microbial growth, using antibacterial products to control e-coli, whereas the sole dipping treatment was inefficient. The combined use of modified atmosphere packaging MAP and coating treatments further prolonged the shelf-life up to 13 days Mastromatteo et al. As reported by Krasaekoopt and Mabumrungthe effectiveness of chitosan incorporated in the edible methyl cellulose coating on the microbiological quality of fresh-cut cantaloupe was evaluated.
The coating application preserved the overall visual quality, the microbial proliferation and reduced surface whiteness during storage. While the content of total phenolics markedly increased in coated carrot sticks stored under moderate gas levels, it was controlled under low O 2 and high CO 2 levels.
An edible coating with soy or wheat gluten protein as a carrier of thymol and calcium chloride was applied on strawberry by Atress et al. Treating fruits did not exhibit any change in fruit appearance until 9 days of storage.
All treatments maintained ascorbic acid content, firmness, total sugar and reduced the total colony, moulds and yeasts compared to the control. All sanitizers except carvacrol maintained microbiological and overall quality of jalapeno peppers during 27 days.
Carvacrol, using antibacterial products to control e-coli, active ingredient of oregano essential oil, maintained shelf life for only 17 days and reduced sensory acceptability of fresh-cut produce, using antibacterial products to control e-coli. However, carvacrol-treated samples retained the highest levels of photochemical and antioxidant capacity, using antibacterial products to control e-coli.
Juices are food very susceptible to yeasts attack. Generally, heat treatment pasteurizationaseptic packaging or use of weak acids exclude yeast spoilage. The anti-yeast effects of these essential oils were good in the acidic pH range optimal for yeasts growth. Synergism or additive effects were recorded by combining the different active compounds.
The most interesting result of the study of Tserennadmid et al. Although the influence of smell-taste of some active agents is known, it has not often been evaluated to a sufficient degree.
One solution to the above-mentioned problem may be the use of combinations of different food preservation systems that would give the benefits of each of them while at the same time appreciably reducing the amount of antimicrobial required.
By using this method, a stable and, from a microbiological stomach bloating and gastric cancer, safe food can be produced without any loss in sensory quality. Fresh dairy products are ready-to-eat foods easily contaminated by undesirable microorganisms. Some of them are spoilage microorganisms which may produce unwanted visual appearance and diminish the commercial value of cheese, other ones are pathogens that affect product safety.
Moreover, fungal spoilage can also occur. Recently, using antibacterial products to control e-coli, some studies have recorded the efficacy of natural compounds, alone or in combination with other preservation methods, when directly applied to milk Cava et al.
Antimicrobials may also be spread onto the packaging materials that come using antibacterial products to control e-coli contact with the cheese or incorporated into the plastic films used for packaging Conte et al. A brief overview of some recent examples of natural active agents applied to cheese is reported, using antibacterial products to control e-coli. The effectiveness of lysozyme and EDTA on microbiological shelf life of mozzarella cheese was studied by Sinigaglia et al.
Mozzarella was packaged in a using antibacterial products to control e-coli that contained lysozyme 0. The packaging system significantly inhibited growth of coliforms and Pseudomonadaceaewithout affecting the typical lactic acid bacteria, using antibacterial products to control e-coli. N 2thus demonstrating that these compounds were valid to prolong cheese shelf life, especially at high lysozyme concentrations.
Different release systems containing nisin and natamycin were also used in various works to create an additional hurdle for spoilage microorganisms in dairy products. For example, edible coatings made of galactomannans incorporating nisin were tested against L.