BioScience Blog – Научный Биологический блог

Bacteriocins (low molecular weight peptides) which manifest active and wide spectrum of anti-pathogen activities have been identified. Most of these substances have failed as food preservatives in practical applications. We propose to identify low molecular weight non-protein compounds produced by isolated bacterial strains which produce a wide spectrum of activity against pathogenic bacteria and especially associated with poultry. Recently it was found specific low molecular weight compound produced by lactic acid bacteria. These organisms are classified as Generally Recognized as Safe (GRAS) and therefore, could be quickly accepted by regulatory concerns to enable widespread application in processing plants. Multiple strains producing various compounds would be required to assure the undesired consequent development of resistant target bacteria. Centers of disease control indicate that approximately 76 million cases of food-borne illness occur in the United States annually. Consequence of these diseases are the resulting 5,000 deaths annually and the estimated $9.2 billion in losses (Mead et al., 1999). This is being a big problem in Kazakhstan. Poultry and poultry products contribute an important part of this human health problem. The most frequently noted association is with Salmonella spp. and Campylobacter jejuni but there is also concern over transmission of enterohemorragic E. coli, Clostridium perfringens and Listeria monocytogenes. These concerns over food safety have increasingly become a matter of public anxiety and concomitantly, have become a financial burden for poultry industry. These public pressures have brought to bear upon the FSIS, who responsibility to regulate matters of public food safety. In turn, FSIS has created the “Mega-Reg” which attempts to regulate allowable levels of Salmonella spp. on processed foods of animal origin. As benchmark, the regulation indicates that the poultry industry should have fewer than 20% of processed carcasses per lot contaminated with Salmonella. In response, the industry improved process control in the USA by increasing the amount of water applied per carcass, employing inside-outside carcass washers and, using counter flow chillers having make-up waters with <50 ppm chlorine or other antimicrobial substances. Even when a plant is within HACCP compliance, processors are not consistently able to meet the specifications of the Mega-Reg. In part, this is due to the persistent and enormous contributions to contamination made during poultry production. Poultry are produced in farms throughout the United States with limited ability to control biosecurity. It is clear that pathogens may be transmitted from the surrounding environment into poultry flocks (Stern et al., 2001; Bailey et al., 2001). One of the more practical interventions was pioneered by Dr. Esko Nurmi of Finland. His contribution entailed the administration of fecal suspensions to newly hatched chicks to reduce the likelihood of Salmonella spp. colonization (competitive exclusion). Variations to this approach have been published and patented but, regulatory resistance to enable marketing of such products has prevented widespread distribution. Consequently, the research for practicable inventions continue, but have as of yet not been forthcoming. Between 10,000 and 20,000 isolates were tested in the laboratory using an analogue a disk diffusion assay with the spot of Salmonella or other pathogen placed on a lawn of the LAB. Once antagonistic bacteria are identified, peptidase enzyme was added to the zone of inhibition to demonstrate inhibition which was not bacteriocin induced in nature. This screening/testing provided the LAB the desired properties. Application of the compounds to known contaminated chicken carcasses in processing plants would be administered and microbial safety of the product would be assessed.