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Multi-mycotoxin testing in food

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by Claire Milligan, Product Manager, R-Biopharm Rh么ne Ltd, UK

or as long as humans have cultivated and stored grain we have been at risk from mycotoxins with outbreaks of Ergots being reported since the Middle Ages in epidemic proportions. Humans have linked the occurrence of mould with sickness since the 7th and 8th centuries and hence conducted a festival to celebrate the Roman God Robigus who was the protector of grain and trees in order to protect from rust and moulds. The problem of mycotoxin occurrence has only gotten larger as our societies have grown more complex and our ever increasing population. The more grain and cereal we consume the greater the chances of us coming into contact with moulds and the mycotoxins that may be present. Fungal growths may be present in cereal grains and can if not detected can cause serious health issues like damage to the immune, cardiovascular, endocrine and nervous systems. Grains such as wheat, barley, oats and rye are extremely susceptible and diseases like head blight can cause substantial agricultural losses, and also lead to problems of mycotoxin contamination by Fusarium fungi. This occurs pre-harvest on the growing crop and can lead to the occurrence of a number of different mycotoxins including deoxynivalenol (DON), zearalenone (ZON), T-2 and HT-2 toxins. Once harvested further problems can arise if the drying is inadequate or cereals are poorly stored. This post-harvest infection can occur with different fungal species leading to contamination with yet other chemically different mycotoxins such as ochratoxin A (OTA) and citrinin (CIT).

prone to fungal contamination is also uniquely susceptible to Fusarium species, which specifically produces mycotoxins known as the fumonisins (FB1 and FB2). In regions with higher temperatures and moisture conditions Aspergillus infection can also appear with subsequent formations of aflatoxin B1, B2, G1 and G2. All of these mycotoxins are unlikely to contaminate the same sample at the same time, but co-occurrence of more than one mycotoxin is certainly common in maize or cereal grain. These mycotoxins are chemically different in structure and therefore each exhibit different toxicological effects, which can be triggered at different levels of exposure. Additionally human and animal species have significantly different degrees of susceptibility to the toxicological effects of these mycotoxins.

Occurrence of multi-mycotoxins in foods

Regulations

Grains are not simply prone to one mycotoxin as where they are grown and environmental conditions can leave them susceptible to more than one toxin. For instance maize while particularly 42 | December 2015 - Milling and Grain

Mycotoxin EU regulatory limit 碌g/kg Cereal type DON

ZON

AFB1

OTA

FB1 + FB2

Bread

500

50

2.0

3.0

-

Cereal-based baby food

200

20

0.1

0.5

200*

Maize breakfast cereals

750

100

2.0

3.0

800

For these reasons and because of the importance of cereals in human diet and animal feed, mycotoxins are tightly regulated in many countries around the world by setting of maximum residue levels (MRLs). As with many other regulations, these limits are much lower for infant and baby foods compared to foods intended for adults. This is because of the additional protection needed during growth and development and the lower body weight of infants In the EU aflatoxins, DON, ZON, FUM and OTA are all regulated in cereals and cereal products, with one limit applying to unprocessed cereals and a lower limit being applied to