| Two studies were conducted on-farm food safety, specifically dairy market beef and diet effects on Escherichia coli O157:H7. In the first study, a national survey of dairy producers was conducted to assess their willingness to improve safety of food products from their farms. The majority considered a veterinarian as their first choice for information concerning dairy market food safety, with more than 33% willing to pay for veterinarians to perform food safety assessments. Nearly half reported that they were well informed by their veterinarian concerning food safety issues. Most producers believed consumer food safety concerns affected their profits, but less than half reported that on-farm HACCP would reduce the risk of foodborne disease. Several reported that they would change practices if they could increase profits, and most preferred that profits come from incentives paid by slaughter establishments. Overall results indicated that producers would benefit from a better knowledge of HACCP.; In the second study, twelve ruminally-cannulated cattle, fed high-forage or high-grain diet with or without monensin, were used to investigate the effects of diet and monensin on level and duration of ruminal persistence and fecal shedding of E. coli O157:H7. Cattle were ruminally inoculated with E. coli O157:H7 (1010 CFU/animal) adapted to nalidixic acid (Nalr). Ruminal and fecal samples were collected for 11 wk and then cattle were euthanized, necropsied, and gut contents were collected. The concentration of Nalr E. coli O157:H7 shed in the feces of cattle fed high-grain diet was higher (P < 0.05) for 1 wk after inoculation and thereafter, the shedding was lower (P < 0.05) than cattle fed the high-forage diet. Cattle fed high-forage diets shed for longer duration ( P < 0.05) than cattle fed high-grain diets. In high-forage fed cattle, the duration of shedding decreased for monensin group compared to no-monensin. At necropsy, E. coli O157:H7 was detected in cecal and colonic contents but not from the rumen. In our study, monensin supplementation decreased the duration of fecal shedding with high forage diet, and the cecum and colon, not the rumen, appear to be the site of persistence of E. coli O157:H7. |
