Microbiological and chemical risk assessments of the addition of selected cereal grains as non-dairy ingredients to dairy products : a thesis presented in partial fulfilment of the requirements for the degree of Master in Food Technology at Massey University, Manawatū, New Zealand

Abstract

Food poisoning cases involving non-dairy ingredients such as cereal grains have been reported. The addition of cereal grains to dairy products in the dairy industry has increased in recent years. This has the potential to contaminate final products with pathogenic, spoilage and toxic chemical contaminants. In this study, the microbial and chemical risks involved in the addition of cereal grains to dairy products were assessed using semi- quantitative risk assessment method.

The results showed that the most critical microbiological hazard in the selected cereal grains is Bacillus cereus due to its ability to form spores and persist in cereal grains. The addition of cereal grains to dairy products with high water activity/moisture content such as liquid breakfast products were found to pose the highest risk. Cyanogenic glycosides (hydrocyanic acid) were found to be the most critical chemical hazard among natural plant toxins in selected cereal grains due to their adverse health effects and abundance in most cereal grains. The addition of cereal grains to dairy products with high solid content was found to pose a very low risk.

The results have identified some knowledge gaps in conducting risk assessments and have also provided background information about the microbial and chemical risks involved in the addition of cereal grains to dairy products. The results highlight the importance of effective implementation of Hazard Analysis and Critical Control Point (HACCP), Good Manufacturing Practices (GMP) and Good Hygienic Practices (GHP) in the dairy industry.