ANIMAL WASTE USED AS LIVESTOCK FEED - DANGERS TO HUMAN HEALTH - REVIEW

Foodborne illness remains a common and serious problem, despite effort s to improve slaughterhouse inspection and food preparation practices. A potential contributor to this problem that has heretofore escaped s erious public health scrutiny is the feeding of animal excrement to li vestock, a common practice in some parts of the United States. In 1994 , 18% of poultry producers in Arkansas collectively fed more than 1,00 0 tons of poultry litter to cattle, and the procedure is also common i n some other geographic areas as a means of eliminating a portion of t he 1.6 million tons of livestock; wastes produced in the United States annually, While heat processing reliably kills bacterial pathogens, i ts use is limited by expense and other factors. Deep-stacking and ensi ling are commonly used by farmers to process animal wastes, but the ma ximal temperatures achieved in stacked poultry litter are typically in the range of 43 to 60 degrees C (110 to 140 degrees F), below the ina ctivation temperatures of pathogenic salmonella and Escherichia coli s pecies, and far below the USDA's recommended cooking temperatures of 7 1 to 77 degrees C (160 to 170 degrees F) for potentially manure-tainte d meat products. In addition to the spread of potential pathogens, usi ng animal wastes as feed presents the possibility that antibiotic-resi stant bacteria may spread from one animal to another and that antibiot ics or other chemicals may be passed between animals, Few research rep orts have addressed the safety of this practice, and those studies tha t have been published have generally been in controlled and artificial environments, rather than in on-farm conditions, Further microbiologi cal studies are recommended to assess the extent of risk. (C) 1997 Aca demic Press.