Doctoral Dissertations

Date of Award

3-1972

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Animal Science

Major Professor

M. C. Bell

Committee Members

R. L. Murphree, R. R. Shrode, M. R. Johnston, R. L. Tugwell

Abstract

Animals exhibiting visible signs of radiation sickness could be an important food resource in the event of a nuclear disaster. Market hogs (Sus scrofa domestica) weighing approximately 200-250 lbs were exposed to a total air dose of 700 R at a rate of 1 R or 45 R/min of gamma radiation from a 60°Co source. Bacteriological studies were conducted on pre- and post-irradiation blood specimens. Muscle, liver and mesenteric lymph nodes were cultured for bacteria 10 days post-irradiation when the animals were slaughtered, and muscle samples were cultured again 5 days post-slaughter during which time the carcas-ses had hung in a cooler. Samples of the teres major muscle were taken at the above times for the following chemical analyses: 1) crude protein, 2) soluble protein, 3) ether extract, 4) moisture content and 5) pH. Cooked loins from carcasses of irradiated and control animals were subjected to sensory panel evaluations. A bacteremic state was not detected in the 1 R/min group nor was there a greater incidence of bacterial isolates from the carcasses of irradiated animals as compared to those from the control animals. Staphylococcus aureus was one of several organisms recovered from the meat. Since several strains are capable of producing an enterotoxin, the safety of the meat for consumption is questionable since no tests are available to rapidly identify these strains. The results of deter-mination of chemical properties indicated no significant differences in ether extract, moisture content, crude protein or soluble protein. The pH of the meat from irradiated animals at slaughter was significantly higher (P < .05) than that of control meat. During the storage phase the pH decreased significantly (P < .01). Taste panel evaluations indicated no drastic flavor differences due to treatment. However, color was significantly affected. All animals exposed to 45 R/min developed a bacteremia at least once during the 10-day post-irradiation period, but this bacteremia was not consistent within the group. Bacterial isolates from the muscles of irradiated animals at slaughter and 5 days later were consistently higher than isolates from controls. These bacteria represented an increased number of genera. Because of the possibility of non-specific and staphylococcal food poisoning, it is recommended that this meat not be consumed. Muscle from irradiated animals yielded significantly more ether extract at slaughter (P < .05) and after 5 days storage, while moisture content was significantly lower (P < .05) at both times. A significant reduction (P < .01) in soluble protein was noted during the storage phase. Muscle from irradiated animals again yielded significantly higher pH values (P < .05), but no difference was noted after the storage phase. Taste panel evaluations indicated less treatment effect on both flavor and color than observed in the low dose rate group.

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