Inhibition of the growth of Salmonella typhimurium and Escherichia coli O157:H7 on chicken feed media by bacteria isolated from the intestinal microflora of chickens

Two lactic acid-producing bacteria, one volatile fatty acid-producing bacterium, and one starch-hydrolyzing bacterium were isolated from the cecal contents of adult chickens. The ability of these bacteria to produce lactic and volatile fatty acids in 5% chicken feed broth media and to inhibit the growth of Salmonella typhimurium and Escherichia coli 0157:H7 on a 5% chicken feed agar media was determined. Inhibition of the growth of the enteropathogens was due to bacteriostatic or bactericidal substances that the cecal isolates produced in the media. Depending on which isolates were used, the inhibitory substances were either high concentrations of lactic acid that created an inhibitory pH in the media or inhibitory concentrations of acetic and propionic acids that the isolates produced in the media.