INTERNAL AND EXTERNAL BACTERIAL COUNTS FROM SHELLS OF EGGS WASHED IN A COMMERCIAL-TYPE PROCESSOR AT VARIOUS WASH-WATER TEMPERATURES

The effects of two egg holding temperatures (15.5 and 26.7 degrees C) and three wash-water temperatures (15.5, 32.2, and 48.9 degrees C) on internal and external shell surface bacterial counts were tested by us ing a commercial-type egg-processing unit. Two experiments consisting of five trials, each of which included 360 eggs per treatment for a to tal of 2,160 per trial, were conducted during two seasons (summer and winter) for a total of 10 replicates pet experiment. During the perfor mance of each replicate, counts from tryptic soy agar (TSA) and MacCon key agar (MAC) were obtained from 10 egg samples which were collected prior to processing (prewash), immediately after washing (postwash), a nd after a 5-day cooling period at 7.2 degrees C (postcool). No growth was observed on MAC plates in either experiment, indicating that fewe r than 100 counts were detected. No significant differences (P > 0.05) were observed in the prewash, postwash, or postcool internal shell co unts of eggs held at 15.5 degrees C compared to internal counts of she lls of eggs held at 26.7 degrees C. Likewise, no significant differenc es (P > 0.05) were observed in the prewash, postwash, or postcool inte rnal shell counts obtained from eggs washed in 15.5 degrees C water co mpared with internal shell counts obtained from eggs washed in water a t 32.2 or 48.9 degrees C. On the basis of our data, spray washing eggs in 15.5 degrees C water does not appear to increase internal shell ba cterial counts. Because warm or hot wash water increases egg temperatu res markedly, a reexamination of cold-water processing procedures may be in order.