Necrotic enteritis (NE) is an enterotoxemic disease caused by Clostridium perfringens that results in significant economic losses, averaging damage of $0.05 per bird. The present study investigated the influence of a dietary supplement, Bacillus subtilis PB6, on performance, intestinal health, and gut integrity against C. perfringens-induced NE in broiler birds. Bacillus subtilis PB6 (ATCC-PTA 6737) is a natural strain isolated from healthy chicken gut that has been shown in in vitro to produce antimicrobial substances with broad activity against various strains of Campylobacter and Clostridium species. The animal study was conducted on broiler chickens (Cobb 400) for the period of 35 d using a completely randomized design. The experimental design included 3 treatments groups. Each treatment group contained 6 replicates, 3 male and 3 female, with 12 birds in each replicate. The 3 treatment groups were an uninfected control, an infected control, and an infected group supplemented with B. subtilis PB6 at 500 g/t of feed, containing 5 × 10(11) cfu/kg. Necrotic enteritis was induced in the broiler birds via oral inoculation of 30,000 oocysts of mixed strains of Eimeria species on d 14 followed by C. perfringens (10(8) cfu/mL) on d 19 through 21 of trial. The birds were analyzed for BW gain, mortality, feed conversion ratio (FCR), intestinal lesion score, intestinal C. perfringens counts, and villus histomorphometry. The infected control group showed markedly thickened mucosa, hemorrhages, intestinal lesions, and ballooning of intestine. The supplementation of B. subtilis PB6 reduced the FCR (P < 0.05) and intestinal C. perfringens counts significantly (P < 0.05) compared with the infected control group. It was also observed that B. subtilis PB6 improved villi length by 10.88 and 30.46% (P < 0.05) compared with uninfected and infected control groups, respectively. The group supplemented with B. subtilis PB6 significantly (P < 0.05) increased the villi length to crypt depth ratio by 49.11% compared with the infected group. In conclusion, the supplementation of B. subtilis PB6 not only controlled C. perfringens-induced NE, but also improved intestinal health in the broiler birds.

Five Leuconostoc strains (CM17, CM19, PM30, PM32, and PM36) previously isolated from Indian meat showed promising antimicrobial activity against food pathogens in screening assay. This study evaluates the efficacy of these isolates against Escherichia coli Microbial Type Culture Collection and Gene Bank (MTCC) 443 and Listeria monocytogenes (MTCC 657) in spinach leaves. Challenge studies were conducted by inoculating E. coli and L. monocytogenes at 6 to 7 Log 10 CFU/g of the leaves respectively and treating them with cell free supernatant (CFS) of 48 h cultures of the isolates. The samples were stored at 4°C and analyzed over a period of 5 d. The study was conducted in triplicates and statistical analysis was carried out using one-way Anova. The counts of the pathogens did not increase over the 5 d period in the control samples, without any treatment. Whereas in the case of CFS treatments, significant reduction (p<0.05) was observed in both E. coli and L. monocytogenes from 1 to 5 d with all the 5 strains as compared to the control. The counts of Listeria dropped by 0.5 to 1 log by 5 d, with PM 36 showing the highest reduction (1 log). In the case of E. coli , 1.1 to 1.5 log reduction was observed by 5 d, with again PM 36 showing the highest reduction (1.5). The overall results indicate that the isolates (specifically PM36) not only showed efficacy in in vitro studies but are also proved to be effective in food matrix making them potential clean label antimicrobial alternatives for food application.

Background: World Health Organization has estimated that 1 in 10 people fall ill and 4, 20, 000 die every year from eating contaminated food. Food pathogens like Escherichia, Salmonella, Staphylococcus and Listeria pose a serious threat to human health. Objective: The objective was to isolate microbes from meat stored at refrigerated conditions and evaluate the antimicrobial activity of the cell-free supernatant against food pathogens. Methods: Chicken and Pork samples were procured and stored at refrigerated conditions (4-7ºC) for 2 weeks. The samples were plated on to Nutrient agar (NA) and De Man, Rogosa and Sharpe (MRS) agar for isolation of aerobic and lactic acid bacteria. Cell-free supernatants of the isolates were screened for antimicrobial activity against Escherichia coli, Salmonella typhimurium, Listeria monocytogenes and Staphylococcus aureus by microtiter plate assay. The 5 most - effective strains were screened for hemolytic activity and identified by 16s rRNA sequencing. Results: A total of 110 strains were isolated, out of which the top 5 most - effective strains were all from MRS agar. They showed 88-90% inhibition against E. coli and S. typhimurium, whereas 60 to 70 % against S. aureus and L. monocytogenes. These strains were found to be non - hemolytic and were identified as Leuconostoc spp. namely, L. mesenteroides subsp. mesenteroides J18, CP003101; L. mesenteroides LM2; L. mesenteroides ATCC 8293, CP000414; L. gelidum subsp. gasicomitatum LM G 18811 and L. mesenteroides; LM2, AY675249. Conclusion: Leuconostoc are known to be effective in controlling foodborne pathogens and therefore, these strains have the potential for application in food and human.