Use of egg washwater pH to prevent survival of Salmonella at moderate temperatures.

The survival and thermal resistance of Salmonella typhimurium N+L141083 was examined in egg washwater at moderate temperatures over a range of pH values. Salmonella were able to grow at 38 and 42 C when washwater pH was less than or equal to 9.5, but substantial lethality was noted at greater than or equal to pH 10. At pH 10.5 and 11, Salmonella were eliminated within 5 hr. At 6 C, Salmonella levels were maintained for 18 hr without lethality up to pH 11. At pH 11, some lethality was noted after 5 hr. A D42 value at pH 7.0 could not be calculated, but at pH 10, a value of 40.8 sec was determined. Narrow range pH paper (pH 8 to 10) responded to egg washwater contact at or above pH 10 with a clear color reaction. Below pH 10, the paper signalled the need for addition of alkaline detergent to prevent the growth of Salmonella.