Prevalence of bacterial contamination of powdered infant feeds in a hospital environment

S Afr Med J. 2007 Jul;97(7):534-7.


Background: The study arose as part of a best-practice nutrition model regarding the introduction of ready-to-use (RTU) infant feeds in place of powdered infant feeds (PIFs) as a standard formula for infants under the age of 1 year who are unable to be breastfed. Internationally and locally there is grave concern regarding the safety and efficacy of mixing PIFs, especially in a hospital setting, and the resultant bacterial contamination causing enteric infections, especially in premature, immunocompromised and sick infants.

Objective: To evaluate the prevalence of bacterial contamination of PIFs given to infants at Red Cross War Memorial Children's Hospital, Cape Town.

Methods: Quantitative levels of bacterial contamination were determined and were expressed as colony-forming units (CFUs) per millilitre of sample. Aliquots of milk were inoculated onto agar, and the milk samples were then incubated at 25 degrees C overnight (N = 10), 30 degrees C overnight (N = 48) and 30 degrees C for 6 hours (N = 34). Post-incubation milk samples were cultured again. Contamination was defined as any positive culture before administration (i.e. pre incubation) or > 10(2) CFU/ ml after administration (i.e. post incubation).

Results: Fifty samples of PIFs (N = 82) were contaminated pre incubation, with 25/82 samples (30.4%) being heavily contaminated ( >or= 10(4) CFU/ml). Post incubation, 43/92 samples (46.7%) were contaminated with > 102 CFU/ml. The acidified PIFs appeared to have some bactericidal effect against some of the organisms, but not all.

Conclusions: RTU infant feeds are sterile and are recommended for use in all hospitalised infants. The results of this study indicate that even when milk is prepared in a controlled environment there is significant bacterial contamination of PIFs post production. As RTU feeds are now readily available in South Africa every attempt should be made to use a sterile RTU system for hospitalised infants.

MeSH terms

  • Colony Count, Microbial
  • Food Contamination / statistics & numerical data*
  • Food Handling
  • Food Microbiology*
  • Food Service, Hospital
  • Humans
  • Infant
  • Infant Formula*
  • Powders


  • Powders