Microbial Flora of Raw and Pasteurized Egg Albumen

Abstract

SummaryGram negative bacteria were the main spoilage organisms of raw albumen stored at 5, 10, 15 or 20° and were identified as strains of pigmented and nonpigmented Pseudomonas, Acinetobacter and Enterobacter liquefaciens. Only one unidentified Gram negative motile rod which failed to attack glucose was found to survive pasteurization in egg albumen (pH 9‐1) at 57.2° for 3 min. Other Gram negative bacteria isolated from one batch of stored albumen were shown to be heat sensitive, so that recontamination had probably occurred after pasteurization. Most of the organisms which survived pasteurization were found to be faecal streptococci, strains resembling Aerococcus viridans, Microbacterium lacticum and two groups (B and C) of unidentified catalase negative rods, or coccobacilli which in many respects resembled the atypical lactobacilli of Thornley & Sharpe (1959). Of these strains only the faecal streptococci and groups B and C were isolated from stored albumen. The effect of the spoilage flora on the ‘catalase’ activity of albumen before and after pasteurization has been studied in relation to the possibility of a ‘catalase’ test being used to monitor the pasteurization process.