A study in the journal Food Microbiology by Nikki De Clercq and Ghent University researchers said that confectionery fillings were generally microbiologically stable because alcohol or preservatives were usually added.
However, confectioners have begun to move away from these ingredients for clean label formulations and to cater for countries that do not consume alcohol.
Spoilage and reduced shelf life
“Such changes in composition can influence the shelf life of the product and may lead to spoilage by xerophilic fungi,” said the study.
“Microbiological stability of chocolate confectionery products could be compromised in the search for alternative (non-alcoholic or ‘clean label’) formulations.”
To reach their conclusions, the researchers evaluated seven Belgian chocolate factories. They obtained air samples from the kitchens, production lines and packing areas and collected samples of various confectionery filling ingredients such as nuts, fruit, ganache and fondant sugar.
Nut contamination
The confectionery factory environment had a low presence of fungal spores, but nut inclusions were flagged as the main source of contamination. The nut samples analyzed showed fungal levels of 10-100 colony forming units (CFU) per gram.
Walnuts were the worst offenders. “One explanation for this could be the lack of heat treatment of walnuts, in comparison to other types of nut preparations such as brésilienne,” said the researchers.
Ganache, fruit fillings and fondant sugar showed no or low fungal counts.
Air contamination
Fungi contamination in the air of the Belgian chocolate factories was also deemed to be low.
The most prevalent species found in the confectionery factory environment has not yet been identified as a spoiler of chocolate products.
The general fungal spore load in the factories was between 50-250 colony forming units per cubic meters of air (CFU/m³) .
There are no agreed standards for air quality in dry food processing environments, but the Government of Flanders did set a guideline in 2004 that fungal spore loads should be maintained below 200 CFU/m³.
More research needed on quality impact
De Clercq’s study found no significant variations on fungal levels in the different parts of the factory, which the researchers said may be because the kitchens, production lines and packing areas are normally so close together.
Previous research has found the fungal spore load to be far higher in bakeries (85-2850 CFU/m³) due to flour, which contains high levels of fungal spores.
The Ghent University study called for more research on the impact of fungal presence on chocolate shelf life and quality.
Source:
Food Microbiology, Vol. 46, April 2015, pps 322–328
‘Detection and identification of xerophilic fungi in Belgian chocolate confectionery factories’
Authors: Nikki De Clercq, Els Van Coillie, Els Van Pamel, Bruno De Meulenaer, Frank Devlieghere, Geertrui Vlaemynck