Smallholder dairy processing in Zimbabwe: the production of fermented milk products with particular emphasis on sanitation and microbiological quality

Abstract

Microbiological quality and hygienic practice during the production of naturally sour milk (NSM), made of unpasteurised milk, and cultured milk (CM), made of pasteurised milk, were studied at three smallholder dairies in Zimbabwe. Petrifilm™ was used for the determination of Escherichia coli, coliforms and aerobic mesophilic count (AMC). AMC Petrifilms used as contact plates showed that 52% of utensils at the dairies ( N=80) were not acceptably clean (>100 CFU per 20 cm 2 ). E. coli was found in 81% of the samples of NSM ( N=31) and in all samples of CM ( N=70). Approx. 39% of NSM samples and 47% of the CM samples contained more than 1000 CFU E. coli ml −1. The high numbers of E. coli found in pasteurised milk emphasise the need for improved hygiene practice at the dairies. Since NSM is not pasteurised, the hygiene at the farm is additionally important for production of NSM. The hygiene and handling at the farm should therefore be especially emphasised at the dairies where NSM is commonly produced.