Innovative technologies for the natural biopreservation of meat

by Dr S. Talukder, Arvind, Lalchamliani To harmonise consumer demands with and Tarun pal Singh, Division of the necessary safety standards, traditional Livestock Products Technology, Indian means of controlling microbial spoilage and Veterinary Research Institute, Izatnagar, safety hazards in are being replaced Bareilly-243122, Utter Pradesh, India. by combinations of innovative technologies that include biological systems eat has long been considered as a such as bacteria (LAB) and/or highly desirable, nutritious and their metabolites. Mprotein rich , but at the same The harmful side effects of chemical time, unfortunately, it is also highly preservatives made the negative perception perishable because it provides the nutrients and this, along with the increasing demand needed to support the growth of many for minimally processed foods with long types of micro-organisms. Due to its unique and convenience, has stimulated biological and chemical nature, meat research interest into finding natural and undergoes progressive deterioration from effective preservatives. the time of slaughter until consumption. The use of micro-organisms and their Traditionally, a great number of foods The main process of quality degradation of natural products for the preservation of have been protected against spoiling by fresh and processed meat is initiated by foods (biopreservation) has been a common natural processes of . spoilage or pathogenic microbial practice in the history of mankind. Currently, fermented foods are increasing proliferation, and it should be controlled to Biopreservation refers to the extension of in popularity (60% of the diet in guarantee the microbial safety of foods. A the shelf-life and improvement of the safety industrialised countries) and, to assure the combination of factors can be an efficient of foods using micro-organisms and/or their homogeneity, quality, and safety of way to warrant food safety keeping their metabolites. products, they are produced by the organoleptic and functional properties. Among alternative intentional application in raw foods of technologies, particular attention has been different microbial systems (starter/ paid to biopreservation to extend the shelf- protective cultures). Meeting consumer demands life and to enhance the hygienic quality, Moreover, because of the improved minimising the impact on the nutritional and organoleptic qualities of traditional Modern technologies associated with food organoleptic properties of perishable food fermented food, extensive research on its processing and microbiological food safety products. Biopreservation rationally exploits microbial biodiversity has been carried out standards have reduced but not eliminated the antimicrobial potential of naturally with the goal of reproducing these qualities, the likelihood of food-related illness and occurring (micro-) organisms in food which are attributed to native microbiota, in product spoilage in industrialised countries. and/or their metabolites with a long history a controlled environment. Food spoilage refers to the damage of the of safe use. , bacteriophages and original nutritional value, texture, flavour of bacteriophage-encoded enzymes fall in this the food that eventually render food harmful concept. Microbial metabolites to people and unsuitable to eat. During the last few decades, investigation on food One of the few possible solutions of preservation has focused on meeting Biopreservatives biopreservation is based on the concept of consumer demands for more natural and using food-grade micro-organisms in food healthier food. In order to achieve improved Biopreservation, as commented above, can itself. These mechanisms are part of the food safety against pathogenic and spoilage be defined as the extension of shelf life and natural balance in complex microbial micro-organisms, the have food safety by the use of natural or ecosystems. used chemical preservatives or physical controlled microbiota and/or their By exploiting the fittest of the naturally treatments (for example high antimicrobial compounds. occurring micro-organisms in temperatures). One of the most common forms of food organoleptically appealing food products, it These preservation techniques have many biopreservation is fermentation, a process is conceivable to design preservation drawbacks which includes the proven based on the growth of micro-organisms in systems that ensure an adequate safety and toxicity of the chemical preservatives foods, whether natural or added. shelf life while maintaining the desired (nitrites), the alteration of the organoleptic These organisms mainly comprise lactic quality of the food product. and nutritional properties of foods, and acid bacteria, which produce organic acids The biopreservation principles from food- especially recent consumer demands for and other compounds that, in addition to grade micro-organisms can be categorised safe but minimally processed products antimicrobial properties, also confer unique according to the antimicrobial compound without additives. flavours and textures to food products. 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International Meat Topics — Volume 6 Number 3 7 Continued from page 7 (, other metabolites, bacteriophages, enzymes) as well as product format (purified antimicrobial, fermentate, protective culture). Not all microbial inhibitory mechanisms are fully understood and not all antimicrobial metabolites from food grade micro-organisms have yet been discovered. It is highly likely that the near future will species of Clostridium, Enterococcus, level used was not further elucidated. bring new understanding and discoveries, Carnobacterium, Lactobacillus, Pediococcus Certain oils stand out as better which will further expand the options for and occasionally Streptococcus and antibacterial than others for meat natural food biopreservation systems. Leuconostoc. These bacteriocins have thus applications. Eugenol and coriander, clove, primarily been tested in foods for their oregano and thyme oils were found to be antilisterial properties. effective at levels of 5-20 μl/g in inhibiting L. Nisin In meat products: Lactobacillus sakei monocytogenes, A. hydrophila and together with 50% carbon dioxide autochthonous spoilage flora in meat Nisin is a cationic, amphiphilic peptide prevented outgrowth of L. monocytogenes products, sometimes causing a marked initial produced by various strains of Lactococcus in bologna-type sausage without an reduction in the number of recoverable lactis, which has a relatively broad target unacceptable pH drop. Pediococcus cells. spectrum that inhibits a wide range of acidilactici was efficient in reducing L. The activity of oregano EO against Gram-positive bacteria. It belongs to the monocytogenes in dry-fermented Spanish Clostridium botulinum spores has been lanthionine-containing bacteriocins and has a sausages. L. sakeii prevented listerial growth studied in a vacuum packed and pasteurised long history of safe use in food. in a pork meat system while enhancing minced (ground) pork product. Active Nisin is a linear lantibiotic that exerts its protein hydrolysis. packagings with the packaging materials antibacterial action through inhibiting cell delivering can play an wall formation as well as forming membrane important role. pores. Effective use of nisin has been Use of essential oils demonstrated both for shelf-life and safety purposes in various types of food, including Preservative agents are required to ensure Conclusion processed meats. that manufactured foods remain safe and unspoiled. Antimicrobial properties of Bio-preservation can provide the potential essential oils (EOs) reveal that Gram- to extend the storage life and food safety Natamycin positive bacteria are more vulnerable than using the natural microflora and (or) their Gram-negative bacteria. antibacterial products. Natamycin is classified as a macrolide A number of EO components have been Shelf life of meat and meat products can polyene antifungal and is characterised by a identified as effective antibacterials, for be extended and safety ensured by the use macrocyclic lactone-ring with a number of example carvacrol, thymol, eugenol, of natural or controlled microbiota and/or conjugated carbon-carbon double bonds, it cinnamaldehyde and cinnamic acid, having their antimicrobial compounds. is being produced by Strepyomyces minimum inhibitory concentrations (MICs) This food preservation process can be natalensis. at higher dilutions in vitro. effectively used in combination with other Natamycin has a low solubility in water, EOs comprises a large number of preservative factors (called hurdles) to but the activity of neutral aqueous components and it is likely that their mode inhibit microbial growth and achieve food suspensions is very stable. Natamycin is of action involves several targets in the safety. stable to heat and it is reported that heating bacterial cell. The potency of naturally Application of hurdles is not only processes for several hours at 100ºC lead to occurring antimicrobial agents or extracts economically attractive; it also serves to only slight activity losses. from plants, ranges of microbial improve microbial stability and safety, as Natamycin is active against almost all susceptibility and factors influencing well as the sensory and nutritional qualities foodborne yeasts and moulds but has no antimicrobial action and their antioxidative of a food. effect on bacteria or viruses. Natamycin acts properties, aimed at food preservation are The principle hurdles employed in food by binding irreversibly with ergosterol and all important. Methods employed for safety are temperature (higher or lower), other sterols, which are present in the cell estimation of inhibitory activity, mode of water activity (aw), pH, redox potential membranes of yeasts and vegetative action and synergistic and antagonistic (Eh), chemical preservatives, vacuum mycelium of moulds. effects and the potential value of these packaging, , HHP, UV agents as natural and biological preservatives and competitive flora (LAB producing should be considered. antimicrobial compounds). Bacteriocin A high fat content appears to markedly A crude bacteriocin-like substance can be reduce the action of EOs in meat products. applicable to meat and products to Micro-organisms produce a diverse range of It is generally supposed that the high levels determine its preservation action on microbial defence molecules, including the of fat and/or protein in foodstuffs protect endogenous microflora and on added B. classical antibiotics, numerous types of the bacteria from the action of the EO in cereus. However, the application of protein exotoxins, lytic agents, metabolic some way. For example, if the EO dissolves biopreservation technology to these byproducts, and bacteriocins. in the lipid phase of the food there will be products should be integrated as part of an Bacteriocins are ribosomally synthesised, relatively less available to act on bacteria overall good manufacturing practice extracellularly released antimicrobial present in the aqueous phase. program and, in combination with peptides that have a bactericidal or One study found that encapsulated refrigeration, is a promising approach for bacteriostatic effect on other micro- rosemary oil was much more effective than maintaining product safety. n organisms. Bacteriocin production is a standard rosemary EO against L. common feature of food-grade lactic acid monocytogenes in pork liver sausage, bacteria (LAB). They are generally active although whether the effect was due to the References are available against Listeria species, and against some encapsulation or the greater percentage from the authors on request

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