Cocoa powders in heat-treated beverages, spoilage risk research

NIZO, an independent contract research company, and its consortium partners have published a paper on a reliable and practical method for enumerating bacterial spores in cocoa powders.

The method was developed as part of a research project involving major cocoa producers, buyers and a packager, and includes expert interpretation on the real-world application of the method to support industry in assessing microbial spoilage.

The consortium includes Olam Cocoa, Cargill and Barry Callebaut; cocoa buying companies The Coca-Cola Company, FrieslandCampina and Abbott Nutrition; and process technology and packaging company Tetra Pak. The paper has been published in the Journal of Food Protection, and is available via Open Access.

The presence of bacterial spores in cocoa powders is inevitable, due to the natural fermentation process of cocoa beans. These heat-resistant bacterial cells can potentially cause food spoilage when they survive heat treatments and can germinate and grow in the finished product.

Usually, spore concentrations in cocoa powders are low, and spoilage incidents rare. However, a reliable method to determine spore concentrations is needed to properly assess the risk of spoilage for finished heat-treated (eg, UHT) dairy products containing cocoa powders. At the same time, results can vary depending on which classical microbiological plating methods are used, making interpretation and reliable risk assessment difficult.

Furthermore, cocoa powders pose added challenges compared to other beverage ingredients, due to factors including their antimicrobial effect, poor wettability and dark colour.

Robyn Eijlander, Senior Project Manager Microbiology and Food Safety of NIZO said: “Food waste continues to be a global problem, and is thus a key focal point for NIZO, as well as for the industrial players who took part in this consortium research project. Reducing food spoilage is an important pillar in decreasing food waste, and every player in the food production chain needs robust methods to assess the risks. As an independent research and knowledge company, NIZO brought together the different players — producers, buyers and processors — to develop and publish an agreed upon method. NIZO also provides expert interpretation, consultancy and support for applying this method in practice.”

Image courtesy of NIZO.