With a practical method for determining concentrations of bacterial spores in cocoa powders, NIZO supports industry to assess microbial spoilage risks in heat-treated dairy products.
The presence of bacterial spores in cocoa powders is inevitable, due to the natural fermentation process of cocoa beans. These spores are heat resistant forms of bacterial cells that can potentially cause food spoilage when they survive heat treatments and are able to germinate and grow in the finished product.
Usually, spore concentrations in cocoa powders are low, and spoilage incidents rare. However, a reliable method of determining spore concentrations is needed, to properly assess the risk of spoilage for finished heat-treated (e.g. UHT) dairy products containing cocoa powders. At the same time, the results will vary when different classical microbiological plating methods are used, making interpretation and reliable risk assessment difficult. Finally, cocoa powders pose added challenges for enumerating spores compared to other beverage ingredients, due to its antimicrobial effect, poor wettability and dark colour.
NIZO and its industrial consortium partners Olam Cocoa, Cargill, Barry Callebaut, The Coca-Cola Company, FrieslandCampina, Abbott Nutrition and Tetra Pak, have published a paper providing an optimised and aligned method for reliable enumeration of spores in cocoa powders. It includes expert insights on interpreting the results in practice.
This paper provides an important reference for cocoa producers and buyers worldwide to reach agreement on acceptable specifications of spores in cocoa powders for assessing spoilage risks of finished liquid products.