Abstract
Poultry feed samples (mash) obtained from a commercial mill were inoculated with either 100 or 5,000 cells/g of a marker strain of Salmonella montevideo. Samples (125 g) were then placed in a microwave oven at power settings of 1.5 or 2.0 kW for 60, 90, or 120 sec; a hot air oven at 99 C (210 F) or 110 C (230 F) for 15, 30, 45, or 60 min; or a flowing steam chamber for 1, 5, 10, or 20 min. Temperature, moisture, and presence of the inoculated S. montevideo were determined in all samples before and after treatment. Feed samples placed in the microwave oven reached a maximum temperature of 186 C (367 F) and had a final moisture content as low as .8%. About 25% of the samples inoculated with 100 cells/g and about 40% of those inoculated with 5,000 cells/g remained positive after treatment. In the hot air oven, feed reached a maximum temperature of 93 C (200 F) with a moisture level after heating of about 4%. Salmonellae were recovered from 35 and 60% of the low and high inoculum level samples, respectively. In flowing steam, maximum feed temperature was 90 C (194 F) with a final moisture level of 15%. After 1, 5, 10, and 20 min of flowing steam, 100, 90, 60, and 0% of the samples were found to contain salmonellae, respectively. All treatments occasionally eliminated salmonellae from the samples, but results were inconsistent and unpredictable.