Microbiological contamination of enteral formulas used in hospitals

Abstract

Objective: to determine the microbiological quality of 2 ready to use enteral formulas ADN powder (P) and ADN liquid (L).

Methods: the study was carried out in 4 hospitals in Santiago. 144 samples were cultured at time 0 preparation), 2, 4, 6, 8 and 10 hours after preparation. At 24 and 48 hours samples were taken from L kept at 4° C. Counts of mesophils (Me), total coliforms (TC) and faecal coliforms (FC) were measured. The microbial quality standards (MQS) were at time 0 < 1 x 102 UFC/ml of Me and no TC, at time 2,4,6,8 and 10 hours, < 1 x 103 UFC/ml of Me, < 10 UFC/ml TC and no FC. 

Results: the average that fulfilled MQS criteria for P at times 0, 2, 4, 6, 8, 10 hours were; Me: 42%, 75%, 50%, 33% and 25%. For CT 83%, 91.5%, 83%, 75% and 42%. For L at times 0,2,4,6 and 8 hours 100% and at 10 hours 92% for Me, for TC 100% at any time. After 4 hours the difference between the TC of P and L was significant
(p < 0.05).

Conclusions: L fulfills the MQS criteria better than P. Ready to use formulas should be used as a first option. The maximum storage time for L is 10 hours at room temperature, whereas this is 4 hours for Tetra Pak P. L can be opened and stored at 4° C and used during the first 48 hours.