Nizo publishes paper on practical spore enumeration method

Published: 8-Sep-2020

The manuscript includes insights on how to interpret the results, in order to assess spoilage risks for heat-treated liquid beverages

Nizo has published a peer-reviewed paper outlining a practical method for determining bacterial spore concentrations in cocoa powders.

The research project brought together a pre-competitive industrial consortium including cocoa producing companies 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 as a result of 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 assess the risk of spoilage for finished heat-treated (e.g. 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.

Cocoa powders pose added challenges compared to other beverage ingredients, owing to their antimicrobial effect, poor wettability and dark colour.

The members of the consortium aimed to define, optimise and agree on one practical and reliable method to enumerate bacterial spores in cocoa powders, that overcomes these challenges.

This method provides a reference for producers and buyers worldwide to reach agreement on acceptable specifications of spores in cocoa powders for risk assessment of spoilage of finished products.

Robyn Eijlander, Senior Project Manager Microbiology and Food Safety of Nizo comments: “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.”

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