Heat destruction of Salmonella in poultry feed: effect of time, temperature, and moisture.

Salmonella enteriditis in poultry feed declines with increasing time of exposure to heat. The interactions of temperature, time, and moisture and their effect on the thermal death of S. enteriditis were established in a factorial randomized experiment. Two other serotypes were tested, and though there was some variation, the thermal death rate followed the same basic pattern. A number of samples of poultry feed were collected and dried. After drying, the water was added back to give specific percentages of moisture contents. The feed was then inoculated with salmonella and heated at specific temperatures, with samples being removed at certain time intervals. These samples were then cultured, and the surviving salmonella were counted. A linear relationship was obtained when the logarithm of survivors was plotted against the logarithm of exposure time. These results permitted the construction of a graph depicting that the rate of reduction in numbers of S. enteriditis when plotted against increasing temperatures is linear. This linear relationship is apparent for other salmonella serotypes such as S. typhimurium and S. haardt. Our results show that the thermal death rate of salmonella in poultry feed can now be predicted at varying time, temperature, and moisture contents.