MICROBIAL QUALITY OF FOODS PRODUCED BY AN ENHANCED COOK-CHILL SYSTEM IN A HOSPITAL

A total of 1,137 samples representing 77 cook-chill food products were analyzed during a 27-month period. Vacuum-packaged food samples from the same production batch of regular diets or products modified for lo w sodium, low fat, diabetic, or strained diets were analyzed before an d after storage at 1 +/- 1 degrees C for up to 21 days in a hospital's food bank. Samples were analyzed for aerobic counts at 26 degrees C a nd 35 degrees C and for coliforms, staphylococci, Bacillus cereus, Clo stridium perfringens, Escherichia coli, E. coli O157:H7, Listeria spp. , Salmonella spp. and Staphylococcus aureus. None of the samples conta ined C. perfringens, E. coli, E. coli O157:H7, or Salmonella. Listeria was isolated from one production batch of asparagus which had been in adequately heated and cooled due to overloading of the vat. S. aureus was isolated (< 100 CFU/g) from 2 samples (beef roast, stewed tomatoes ) and B. cereus was isolated (<100 CFU/g) from several pasta and bean products. Low-fat products had higher (P < 0.05) aerobic populations t han products modified for low sodium, low fat, diabetic, or strained d iets. No differences were obtained between the before- and after-stora ge populations. Over 92% of the samples had aerobic populations of 3 l og CFU/g or less and 98% had populations of 4 log CFU/g or less. All e xcept 2 samples had coliform populations of 1 log CFU/g or less and al l samples had staphylococci populations of 3 log CFU/g or less. Under the conditions of this study, the microbial quality of vacuum-packaged foods properly produced by an enhanced cook-chill system was acceptab le after food storage at 1 +/- 1 degrees C for up to 21 days.