Naturally contaminated corn implicated in an outbreak of equine leukoencephalomalacia (ELEM) in southeastern Arizona was analyzed for mutagenic potential using the Salmonella/microsome mutagenicity assay before and after treatment with the ammonia procedure. Crude acetonitrile: water (1 + 1) extracts of high-pressure/ambient temperature (HP/AT) ammonia decontaminated, HP/AT plus low pressure/high temperature (LP/HT), and non-ammoniated fumonisin contaminated corn were tested for mutagenic potentials. Relatively pure (approx. 90%) fumonisin B1 standard was also tested for comparison purposes. The results of this experiment indicate that there was no mutagenic potential for the fumonisin B1 standard at the concentrations tested (100 micrograms/plate). Also, neither the naturally-contaminated corn nor the ammonia decontaminated samples elicited a positive mutagenic response. Fumonisin B1 levels, as determined by HPLC methods, were reduced by an average of 79% via the ammonia decontamination process. It is encouraging to note that, while further work is necessary to increase the efficacy of the ammonia process to reduce fumonisin levels, the ammonia process did reduce fumonisin levels and no mutagenic potentials were apparent in the treated corn.
The efficacy of the buffered sodium hypochlorite solution, Bionox, in controlling bacterial contamination was evaluated on fresh-cut poultry (chicken, light and dark meat), fish fillets, fruit, and vegetables. Food products were immersed in a nutrient broth suspension of Salmonella enteritidis (ATCC #13067) for 30 s and allowed to drip/air dry for 10 s prior to exposure to the sanitizing agent. Food products were then each vigorously washed with 100 ml of buffered peptone which was plated in serial dilution on XLD-N agar and incubated at 37°C for 24 h. Typical Salmonella colonies as well as non-Salmonella colonies growing on the XLD-N plates were counted and identified. Results showed the sanitizing solution to be effective in reducing S. enteritidis on all test foodstuffs. Count reductions of 4, 3, and 2 logs per gram on chicken, vegetables, and fruit, respectively, were achieved. Salmonella reductions of two logs were also achieved on fish fillets, but the sanitizer performance depended to some extent on the background bacterial flora present prior to the addition of the Salmonella test organism. The effect of the sanitizing solution on protein functionality, lipid oxidation, and starch degradation was determined using protein dispersibility and solubility assays, peroxide and iodine values, and changes in reducing sugars levels, respectively. Results showed no adverse effects on these parameters after exposure of the food products to the sanitizing solution.
Milks obtained from cows fed rations containing aflatoxin-contaminated cottonseed, ammonia-treated aflatoxin-contaminated cottonseed, and uncontaminated cottonseed were tested for mutagenic potential using the Salmonella/mammalian microsome mutagenicity assay using Salmonella typhimurium strains TA98 and TA100. Standard assay protocol was used with S-9 liver homogenate added. Samples including whole milk, nonfat dry milk powder, cream, and reconstituted whole milk were applied directly to the plates in triplicate. As a control, samples of whole milk, reconstituted whole milk, and nonfat dry milk powder from cows fed uncontaminated feed were spiked with aflatoxin B1 and tested for mutagenic activity. High levels of mutagenic activity were observed in all samples from cows exposed to aflatoxin-contaminated cottonseed and the aflatoxin-spiked milks. This high activity was not evident in whole milk and whole milk component samples from cows fed the ammonia-treated aflatoxin-contaminated cottonseed or nonaflatoxin containing cottonseed. A low level of mutagenic potential was evident in whole milk from the ammonia treated group using TA100 tester strain.
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