Antagonistic Action of Cells of Lactobacillus lactis toward Escherichia coli O157:H7 on Refrigerated Raw Chicken Meat

Abstract

Cells of a strain of Lactobacillus lactis selected for ability to produce hydrogen peroxide were added to Trypticase soy broth (TSB) containing Escherichia coli O157:H7 to determine if L. lactis was antagonistic towards the E. coli during storage at 7 degrees C for 7 days. E. coli was enumerated on violet red bile agar. Three strains of E. coli O157:H7 (43894, 43890, and 35150) were evaluated. Control samples containing no L. lactis did not show significant declines in numbers of E. coli during the 7 days of storage. however, samples inoculated with at least 5.0 x 10(7) L. lactis per ml exhibited significant declines in numbers of E. coli after only 3 days of storage for all strains. Samples inoculated with fewer L. lactis displayed vary effects on E. coli O157:H7 depending on the strain E. coli O157:H7 strain 43894 appeared to be the most resistant to the antagonistic action of the L. lactis. Interaction experiments in the presence of catalase indicated that hydrogen peroxide was the main factor responsible for the inhibitory action produced by the lactobacilli. Raw chicken breast meat inoculated with E. coli O157:H7 strain 43894 plus the cells of L. lactis and stored at 5 degrees C exhibited declines in numbers of the pathogen, whereas those inoculated only with the E. coli exhibited no declines during storage at 5 degrees C.

Lactic acid bacteria isolated from chicken carcasses with inhibitory activity against Salmonella spp. and Listeria monocytogenes

“…Actually, the surface of the chicken meat that was inoculated with the strain of Lactobacillus salivarius was clear and with a pleasant odour, whereas on the surface of chicken meat that was kept intact a slight slime appearance had started to grow. Our observations seem to be in accordance with the findings of Brashears et al (1998) where the inoculation of chicken meat with L. lactis exerted control on the growth of psychrotrophic spoilage organisms. Poultry meat usually spoils due to the growth of these psychrotrophic spoilage organisms (Barnes 1976).…”

“…Moreover, the sensorial evaluation proved that the addition of L. salivarius not only reduced the growth of pathogens but also inhibited the growth of slime on chicken meat and improved its overall appearance. The addition of substances to the chill tank of poultry in order to inhibit pathogens has been evaluated in several studies (Brashears et al 1998). Our suggestion would be the addition of L. salivarius as a concentrated culture to the chill tank, among other microbial hurdles that can be applied, in order to improve the safety and to extend the shelf life of chicken products.…”

“…However, the investigation into biopreservation of fresh red meat is rather limited (Muthukumarasamy et al 2003;Senne & Gilliland 2003;Laursen et al 2005) and even scarcer into that of fresh poultry meat (Brashears et al 1998;Maragkoudakis et al 2009). To the best of our knowledge, stock cultures of LAB have been used to check their antagonistic action towards pathogens on raw poultry; on the contrary, LAB isolated from the natural microflora of the skin of poultry carcasses have not been used for the biopreservation of raw poultry products so far.…”

Antimicrobial Substances Production at Refrigeration Temperatures by <i>Lactobacillus delbrueckii</i> MH10: A Candidate for Food Biopreservation

“…The number of viable cells of E. coli O157:H7 in control was not significantly changed in non-permissive temperature. These results are similar with date obtained by Brashears et al [23].…”

Microbial defense systems in foods and feeds

“…Interaction is established by adsorption between the peptide and the target cell, this is facilitated by electrostatic bonding between the cationic peptide and negatively charged molecules of the outer bacterial envelope, such as phosphate moieties of lipopolysaccharides of gram-negative bacteria or lipoteichoic acids occurring on surfaces of gram-positive bacteria. Specific receptors present on the target microbial cell surface serve as primary ignition for biological action of bacteriocins and as a consequence result in the death of the microbial cell in an isolated or concomitant (Brashears et al, 1998). While several nonlantibiotic bacteriocins require a protein receptor to act on non-energized membranes (Montville and Winkowski, 1997), lantibiotic bacteriocins act on energized membranes and do not require protein receptors.…”