Chapter 20 - Biopreservation: an alluring method to safeguard food from spoilage

Abstract

Food preservation is a process to provide safety and security. The recent changes in consumers’ demands for safe but minimally processed products have led researchers to explore natural additives to reduce the risk of health hazards and control microbial growth, thus providing an ecological approach to the problem. Technically, this process is called biopreservation and the natural compounds used in this process are called biopreservatives. Food-borne pathogenic and spoilage microorganisms can be regulated and minimized to acceptable and noninfective doses by this process. A combination of innovative technologies is involved in biopreservation: biological antimicrobial systems such as lactic acid bacteria (LAB) and/or their metabolites. Some natural preservatives are present in several types of food: lysozyme in egg white, a lactoperoxidase system in raw milk, plant antimicrobials such as extracts of herbs, and secondary metabolites produced by microorganisms such as antibiotics and bacteriocins. The antagonistic properties of LAB are derived from competition for nutrients and the production of one or more antimicrobial active metabolites such as organic acids (lactic and acetic), hydrogen peroxide, and antimicrobial peptides (bacteriocins) serve the purpose of guarding the food. Their combined use allows most pathogenic and spoilage bacteria to be controlled and also extended their inhibitory activity spectrum to such intrinsically resistant organisms as the Gram-negative bacteria, Bacillus spp., owing to their broad antimicrobial spectra, and showed their action against Gram-positive and Gram-negative bacteria as well as fungi, and hence can be utilized as candidate biopreservatives in food processing industries. These are peptides with complex structures with antimicrobial activity against other microscopic organisms and related species. Bacteriocin production in Bacillus spp. has been studied in recent decades and shows how to incorporate subtilin from B. subtilis, megacin from B. megaterium, and thermacin from B. stearothermophilus. In a process of achieving food safety, biopreservation is effectively coupled with other hurdles to inhibit microbial growth. Sensory and nutritional attributes of food are preserved when an appropriate blend is used and is economically sound too. These biopreservatives promote the microbial stability of both fermented and nonfermented vegetable food products using bacteriocinogenic strains as starter cultures, protective cultures or co-cultures, and the employment of purified bacteriocins as food additives. On the contrary, the use of bacteriophages and endolysins is also showing a promising perspective. Bacteriophages and phage-encoded endolysins along the food chain, too, have applications in preservation.