A microbiological profile of commercially prepared salads

Samples of commercially prepared chicken salad, ham salad, potato salad, cole slaw, pimento cheese spread and several other types of salads from producers were analyzed microbiologically upon receipt and five days after the expiration date for aerobic plate count, psychrophilic plate count, coliform count and yeast and mold count. Plating was carried out by homogenizing ten grams of each salad with ten milliliters of 2 percent sodium citrate to a pipettable consistency in a Virtis homogenizer and pouring plates. Aerobic plate count ranges of less than 100 to greater than 30 million organisms per gram of fresh salad and from less than 100 to greater than 1.5 billion organisms per gram of salad after the expiration date were found. The psychrophilic plate count range was from less than 100 to 31 million organisms per gram of fresh salad and from less than 100 to greater than 970 million organisms per gram of salad after the expiration date. Coliform plate count ranges were from less than one to 1,990 coliforms per gram of salad after the expiration date. Yeast and mold plate count ranges were from less than one to greater than 300,000 organisms per gram of fresh salad and from less than one to greater than 300,000 organisms per gram of salad after the expiration date.. Bacteria from aerobic plate counts, psychrophilic plate counts and coliform counts were isolated according to differences in colony type and location in the agar. The bacteria were characterized for identification. Identified bacteria included eight species of Bacillus, six species of Lactobacillus, three species of Leuconostoc, five species of Streptococcus, three species of Micrococcus, one species of Escherichia, one species of Enterobacter and one species of Citrobacter. Members of the genera of Pseudomonas, Xanthomonas and Actinomyces were also found.