Researchers in Brazil have found high levels of the potentially lethal contaminant aflatoxin in chocolate and say constant monitoring is required.
The study ‘Co-occurrence of ochratoxin a and aflatoxins in chocolate marketed in Brazil’ published in the Food Control journal evaluated mycotoxins (ochratoxin A and aflatoxins) in 125 samples of powdered, bitter, milk and white chocolate from supermarkets in Brazil.
Mycotoxins are secondary metabolites formed by fungi that have been linked to immune suppression and disease.
Chocolate high in mycotoxins
According to the authors Marina Copettiet al., the presence of aflatoxins in chocolate has rarely been reported. However, they found aflatoxins in 80% of all chocolate examined. Ochratoxin A was also found in 98% of the sample.
They were keen to emphasise the joint occurrence of ochratoxin A and aflatoxin as past research was focussed only on ochratoxin A.
“The consumption of chocolate with high levels of cocoa in the formulation has been stimulated due to health benefits attributed to some cocoa components but on the other hand, these high cocoa content products tend to have the highest amount of aflatoxins and ochratoxin A,” said the study.
“To guarantee a safe consumption of chocolate, there should be a continuous monitoring of both ochratoxin and aflatoxin,” it continued.
Aflatoxin B is classified by the International Agency of Research of Cancer as a Group One carcinogen with mutagenic and teratogenic properties. Its presence in food should therefore be as low as reasonably achievable (ALARA), with no tolerable daily intake (TDI), said the authors.
Dark chocolate suspect
Higher levels of mycotoxins were found in samples of dark chocolate, the form increasingly linked to health benefits.
Bitter dark and powdered chocolate had the highest levels of both ochratoxin A and aflatoxins.
The authors suspected mycotoxin contamination was increased when more fat-free cocoa solids were present. White chocolate, for example, does not have fat-free cocoa solids and fewer mycotoxins were found during the research.
The study added that mycotoxins could be higher in Brazilian chocolate than in cocoa products from other areas, as manufacturers tended to use higher levels of cocoa.
The report said that the sun drying stage was critical to the formation of mycotoxins in cocoa because there is still enough water to sustain fungal growth, which leads to mycotoxin production.
The researchers concluded that further studies were needed to understand how mycotoxins were formed in cocoa to limit their presence in chocolate products.