Starter cultures: bioprotective cultures

Abstract

In the last few years, concerns over food safety have increased their importance due to its dramatic impact on public health. Over the past decade, a series of food scandals have erupted involving meat and meat products, which feature prominently in the food safety crisis. At present, bovine spongiform encephalitis and the rapid spread of avian influenza from eastern to western countries have triggered a sudden lack of consumer confidence in meat products and led to a dramatic fall in demand. The globalization of commerce, the gradual increase in world population and the change in lifestyles have resulted in consumer claims for safety oriented to foods of animal origin. Undoubtedly, the major threat to food safety is the emergence of “new” pathogens. The recent role of Listeria monocytogenes, Escherichia coli O157:H7, Campylobacter jejeuni, Yersinia enterocolitica and Vibrio parahemolyticus as food-borne microorganisms has been related to the increase in food poisoning outbreaks, compared to traditional food pathogens. Changes in the food chain will continue to create opportunities for the emergence of new diseases and the reemergence of old ones (Elmi 2004; Church 2004). In addition, the presence in meat products of chemical additives and residues of agrochemical and veterinary drugs are also perceived by consumers as a health risk. Even when the level of these residues seldom exceeds regulatory limits in meat products (Tarrant 1998), the use of antibiotics in intensive animal production poses the additional risk of bacterial resistance, which constitutes a microbiological hazard. On the basis of these data, the need emerges for solutions to the problem of food hygienic quality. Consumers are increasingly demanding pathogen-free foods with minimal processing, fewer preservatives and additives, high nutritional value, and intact sensory quality. In response to these conflicting demands, current trends in the meat industry include the investigation of alternatives for safer and healthier products. Biopreservation has gained increasing attention as a means of naturally controlling the shelf life and safety of meat products. The application of bioprotective cultures to ensure hygienic quality is a promising tool. However, it should be considered only as an additional hurdle to good manufacturing, processing, storage, and distribution practices. In the present contribution, the use of antagonist microorganisms to inhibit and/or inactivate pathogens and spoilage flora in meat fermented products is discussed, with particular reference to bacteriocin-forming bacterial strains. A new concept of starter cultures for fermented sausages is analyzed where biopreservative and probiotic features complete the recently established essential criteria for a meat starter culture.