Bacterial populations in complementary foods and drinking-water in households with children aged 10-15 months in Zanzibar, Tanzania

J Health Popul Nutr. 2009 Feb;27(1):41-52. doi: 10.3329/jhpn.v27i1.3316.


Bacteria were quantified in samples of drinking-water and in two porridges prepared for infant-feeding [fortified instant soy-rice porridge (SRP) and cooked porridge (Lishe bora, LB)] in 54 households. Bacterial numbers were measured again after the porridges had been held at room temperature for four hours (T4). Findings were benchmarked against bacterial numbers in traditional complementary foods sampled from 120 households. Total bacteria, coliform, and Enterobacteriaceae counts were enumerated using Petrifilm. The mean log bacterial numbers were the lowest for LB at TO (2.24 +/- 0.84 cfu/g aerobic counts) and the highest for SRP at T4 (4.63 +/- 0.56 cfu/g aerobic counts). The total bacteria, coliform and Enterobacteriaceae counts were higher at T4 than at T0 for LB (p < or = 0.001); however, only the coliform and Enterobacteriaceae counts were higher at T4 than at T0 for SRP (p<0.001). Drinking-water, SRP0, traditional foods, and SRP4 all had the mean aerobic counts higher than the acceptable cut-off but the total bacterial count in SRP0 was not significantly (p=0.543) different from drinking-water. However, coliform and Enterobacteriaceae counts in SRPO were higher than in drinking-water (p<0.001). Also, although the aerobic counts of SRP4 were not significantly (p>0.999) different from traditional foods, the coliform and Enterobacteriaceae counts were significantly higher in SRP4 than in traditional foods (p<0.001). It is, therefore, recommended that food safety concerns be addressed when improving complementary foods.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Colony Count, Microbial
  • Consumer Product Safety
  • Enterobacteriaceae / growth & development
  • Enterobacteriaceae / isolation & purification*
  • Female
  • Food Contamination / analysis*
  • Food Microbiology
  • Humans
  • Infant
  • Infant Food / analysis
  • Infant Food / microbiology*
  • Infant Food / standards
  • Male
  • Tanzania
  • Time Factors
  • Water Microbiology
  • Weaning