Of Moulds and Mycotoxins…
With harvest coming up, farmers and food producers will be keeping an eye on weather forecasts for many reasons. (At the time of writing it looks hot). One of the less obvious reasons will also have many laboratories gearing up for a busy period of testing. Analysing the risk of mould growth on crops.
Mould Growth on Crops
Mycotoxins are a range of naturally occurring compounds formed by moulds growing on food crops during growth and storage. These include aflatoxins, ochratoxin A, the fusarium toxins, patulin, citrinin, ergot alkaloids and alternaria toxins, among others.
And they can be nasty, holding the potential to cause serious illness or death if consumed.
Aspergillus flavus and Aspergillus parasiticus are the main mould species which produce the four aflatoxins (B1, B2, G1, G2). These are found mostly in crops growing in warm, humid climates. Also in nuts, dried fruit, spices, cereals and cereal products.
These toxins can also be found in milk and milk products due to their potential presence in feed for ruminants.
But don’t panic just yet. Food producers do a lot of work to reduce mould formation. They have many steps in their production process to remove or reduce dangerous levels in products.
However, with sprawling supply chains that span countries with varying food standards, paired with recent increases in food fraud, the risk of compromised products reaching the customer is increasing.
Products of particular risk of aflatoxin contamination are olive oil, rapeseed oil and their derivative products. Food companies diligently and stringently mitigate against counterfeiting by using risk-based testing to flush out and deter fraud.
The concentration of these toxins is determined using enzyme-linked immunosorbent assay (ELISA) testing. However, the gold standard test is liquid chromatography tandem mass spectrometry (LC/MS/MS).
LC/MS/MS earns the accolade by being less prone to false positives and false negatives as well as giving a definitive concentration. ELISA can delay production and that can have serious economic consequences. Or, even worse, it can miss these compounds entering the food chain with serious health risk consequences.
However, the most important stage for the detection of these toxins in food is successfully and reproducibly extracting them from the matrices in the first place.
Sample preparation, typically performed manually by an analytical chemist comes with its own challenges. As indicated above, the consequences of false results (either negative or positive) are serious so confidence in the quality of results is extremely important.
Any variability or lack of reproducibility can slow the workflow down if repeat testing is needed causing unhelpful delays in decision making. Unfortunately manual sample prep is often a source of reproducibility issues in an analytical workflow. Then there is the time invested in a manual sample prep and the risk of exposure to potentially harmful compounds.
This is where automated sample preparation comes into its own, as the standards which are usually produced on the bench can be produced robotically. This reduces contact by the analyst and with the toxic compounds themselves, significantly lowering the danger of false positives/negatives.
GERSTEL have automated the sample preparation for the extraction of aflatoxins from oils, improving confidence in the results produced in this type of testing. Whilst this work concentrates on aflatoxins, the automation of sample preparation can be applied to the analysis of most mycotoxins.