Microbiological Performance of Dairy Processing Plants Is Influenced by Scale of Production and the Implemented Food Safety Management System: A Case Study

Abstract

The effects of existing food safety management systems and size of the production facility on microbiological quality in the dairy industry in Kenya were studied. A microbial assessment scheme was used to evaluate 14 dairies in Nairobi and its environs, and their performance was compared based on their size and on whether they were implementing hazard analysis critical control point (HACCP) systems and International Organization for Standardization (ISO) 22000 recommendations. Environmental samples from critical sampling locations, i.e., workers' hands and food contact surfaces, and from end products were analyzed for microbial quality, including hygiene indicators and pathogens. Microbial safety level profiles (MSLPs) were constructed from the microbiological data to obtain an overview of contamination. The maximum MSLP score for environmental samples was 18 (six microbiological parameters, each with a maximum MSLP score of 3) and that for end products was 15 (five microbiological parameters). Three dairies (two large scale and one medium scale; 21% of total) achieved the maximum MSLP scores of 18 for environmental samples and 15 for the end product. Escherichia coli was detected on food contact surfaces in three dairies, all of which were small scale dairies, and the microorganism was also present in end product samples from two of these dairies, an indication of cross-contamination. Microbial quality was poorest in small scale dairies. Most operations in these dairies were manual, with minimal system documentation. Noncompliance with hygienic practices such as hand washing and cleaning and disinfection procedures, which is common in small dairies, directly affects the microbial quality of the end products. Dairies implementing HACCP systems or ISO 22000 recommendations achieved maximum MSLP scores and hence produced safer products.