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.

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

A fermentation process using Lactobacillus acidophilus added to edible food wastes was evaluated for its bactericidal action on selected gram-positive organisms. The Lactobacillus fermentation converts food wastes into an animal feed ingredient. In this study, 5 gram-positive bacteria of zoonotic importance were individually tested. These organisms were: Group E Streptococcus, Erysipelothrix rhusiopathiae, Clostridium perfringens, Corynebacterium pseudotuberculosis, and Listeria monocytogenes. For each experiment, Lactobacillus was first mixed into ground waste; one of the test organisms was then inoculated and mixed. This mixture was divided among eight 5.5-L containers and incubated (duplicates) at 5 C, 10 C, 20 C, and 30 C for 96 hours. Internal waste temperature, reduction-oxidation, and pH were monitored. Waste samples were taken initially and at subsequent 24-hour periods. Qualitative and quantitative recoveries of the test bacteria were attempted for each sample. Group E Streptococcus was reisolated in increasing numbers at all temperatures throughout the fermentation period. Erysipelothrix rhusiopathiae was recovered throughout the 96-hour period at 5 C; at 10 C it was recovered at 24 hours but not at 48 hours. Erysipelothrix rhusiopathiae was killed by 24 hours at 20 C and 30 C fermentation temperatures. Clostridium perfringens survived the entire test period at 5 C, 10 C, and 20 C; it was killed by 72 hours at 30 C. Neither Corynebacterium pseudotuberculosis nor Listeria monocytogenes was reisolated at any temperature at any time.

Survival of viruses in fermented edible waste material.

The survival of selected viruses in fermented edible waste material was studied to determine the feasibility of using this material as a livestock feed ingredient. Seven viruses, including pseudorabies, Newcastle disease, infectious canine hepatitis, avian infectious bronchitis, measles, vesicular stomatitis, and a porcine picornavirus were inoculated into a mixture of ground food waste (collected from a school lung program) containing Lactobacillus acidophilus. Mixtures were incubated at 5 C, 10 C, 20 C, and 30 C for 96 hours. Temperature, pH, and redox potential were monitored. Samples for virus isolation were obtained daily. Newcastle disease virus and infectious canine hepatitis virus survived the entire test period. The porcine picornavirus was inactivated at 30 C after 74 hours, but survived for the entire test period at the other temperatures. Pseudorabies virus was inactivated at 20 C and 30 C within 24 hours, but survived for 48 hours at 10 C and 96 hours at 5 C. Avian infectious bronchitis virus was inactivated at 20 C and 30 C within 24 hours, but survived 72 hours at 5 C and 10 C. Measles and vesicular stomatitis viruses were rapidly inactivated at all 4 temperatures.