Bacterial contamination of hospital-prepared enteral tube feeding formulas in Isfahan, Iran

BACKGROUND: Hospital-prepared tube feedings from three intensive care units of two hospitals in Isfahan, Iran were analyzed for microbial contamination. METHODS: A total number of 152 samples (76 samples each at the time of preparation and 18 hours following preparation) were collected. Standard plate count, coliform count and Staphylococcus aureus count for all samples were conducted. Samples were analyzed also for the presence of Salmonella spp. and Listeria spp. RESULTS: At the time of food preparation, out of 76 samples, 53 samples (70%) had coliform contamination and 87% of these contaminated samples had counts greater than 10(1) cfu/g. Also, 68 samples (90%) had S. aureus contamination greater than 10(1) cfu/g. In standard plate count, 74 samples (97%) had counts greater than 10(3) cfu/g, while 54 samples (71%) had counts greater than 10(4) cfu/g. In second sampling occasion, out of 76 samples, 68 samples (90%) had coliform contamination and 84% of these contaminated samples had counts greater than 10(1) cfu/g. Also, 72 samples (95%) had S. aureus contamination, 98.6% of these contaminated samples had counts greater than 10(2) cfu/g. In standard plate count, 74 samples (97%) had counts greater than 10(4) cfu/g. No Salmonella or Listeria was detected from samples. CONCLUSIONS: The results indicated that a majority of the blenderized enteral tube feedings in those hospitals are not safe. In comparison to the standard limits, these enteral tube feedings are highly contaminated and posed substantial risk for developing a foodborne disease or nosocomial infection.