The relationship between enteral formula contamination and length of enteral delivery set usage

Twenty-one delivery sets were collected from 21 patients who had received continuous Osmolite feedings over 24 hours. Delivery sets were than taken to the laboratory and hung for an additional 48 hours. In the laboratory, the delivery sets were rinsed with tap water and Osmolite was added every 12 hours. Formula samples were obtained from the delivery sets after they had been used for 24 hours, and every 12 hours during the additional 48 hours in the laboratory. Formula contamination was assessed by determining bacterial counts. Unacceptable contamination was defined as bacterial counts greater than or equal to 10(5) cfu/mL. The mean bacterial count was 2.8 x 10(5) cfu/mL at 24 hours, and all subsequent mean counts increased over time. There were statistically significant differences among the mean log bacterial counts at all time periods (p less than or equal to 0.0005) except between 36 hours and 48 hours (p = 0.019). Of the 21 delivery sets, 23.8% were unacceptably contaminated at 24 hours, and by 48 hours, 42.9% were unacceptable. These findings suggest that if 10(5) cfu/mL is used as a criterion, delivery sets should not be used for more than 24 hours in a hospital, and 24-hour use of delivery sets may even be too long.