INCIDENCE OF SALMONELLA IN PENNSYLVANIA EGG PROCESSING PLANTS AND DESTRUCTION BY HIGH PH

Eggs and washwater samples from egg processing plants in southeastern Pennsylvania were examined for total bacterial counts and the incidenc e of Salmonella. Survey data indicated a greater number of microorgani sms survived the washing process when low washing temperatures (32.2 t o 35-degrees-C) and low pHs (pH 9 to 10) were used. Salmonellae belong ing to group D1 were found in washwater and on washed eggs from a plan t which had washwater in this lower temperature and pH range. Plants t hat had washwater with high pH (pH 11.0 to 12.5) and high temperatures (37.7 to 43.3-degrees-C) had relatively low microbial counts in the w ashwater (7.5 x 10(3) CFU/ml), and no salmonellae were detected in eit her washwater samples or on washed eggs. Both washwater pH, and temper ature had a dramatic effect on the survival of Salmonella enteritidis. At pH 11 and temperatures of 32.2-degrees-C (90-degrees-F), 37.7-degr ees-C (100-degrees-F) and 43.3-degrees-C (110-degrees-F), S. enteritid is died rapidly, but at lower temperatures of 4.4-degrees-C (40-degree s-F) and 18.3-degrees-C (65-degrees-F) the death rate was much slower. At pH 9, S. enteritidis was able to grow slowly at 32.2 and 37.7-degr ees-C; however, at 43.3-degrees-C, regardless of pH, S. enteritidis di ed rapidly. High detergent concentration and low egg solids concentrat ion also increased the rate of destruction of S. enteritidis.