Introduction and reisolation of selected gram-negative bacteria from fermented edible wastes

A Lactobacillus fermentation process, using edible food wastes, was tested for its ability to eliminate selected bacterial pathogens. This fermentation process converts food wastes into a feed ingredient for animal consumption. Six gram-negative bacterial pathogens of potential zoonotic importance were tested. These experimental organisms were: Salmonella enteritidis serovar typhimurium, S enteritidis serovar anatum, S cholerae-suis, Yersinia enterocolitica, Y pseudotuberculosis, and Pasteurella multocida. Each organism was introduced into ground waste that had been previously inoculated with L acidophilus, and was mixed. This mixture was divided among 8 containers, and was incubated in duplicate at 5 C, 10 C, 20 C, and 30 C for 96 hours. The temperature of the reactant containers, reduction-oxidation potential, and pH were monitored. Waste samples were obtained initially and subsequently at 24-hour periods for 96 hours. Qualitative and quantitative recovery attempts from each sample were made for the introduced gram-negative bacteria. Pasteurella multocida and the S enteritidis serovars typhimurium and anatum survived the fermentation at 5 C and 10 C, but were killed after 48 hours at 20 C and 30 C. Salmonella cholerae-suis survived at 5 C, but was destroyed by 72 hours at the remaining temperatures. Yersinia enterocolitica was viable through 70 hours, but was killed by 96 hours. Yersinia pseudotuberculosis was not reisolated at any temperature.