Control of aflatoxins in the food industry

ABSTRACT Certain foods such as nuts and treenuts are preferred media for aflatoxin-producing Penicillia and Aspergilli. About 50 per cent of the mouldy nuts examined contained aflatoxins in amounts of up to several hundred ppb. About 10-20 per cent of the mouldy grain products contained aflatoxins in amounts of up to 100 ppb. Aflatoxin was never detected in jams, pickles or potato chips and crisps, even when mouldy. Aflatoxin may penetrate several centimetres into foods in the course of only a few days. In general the aflatoxin content of the mycelium is higher than that of the food underneath and decreases with its distance from the mycelium; however, at a certain depth the aflatoxin content increases again. Even non-mouldy foods or raw materials may contain aflatoxins. Spores can be transferred by insects, especially flies, wasps and bees, or by birds to foods where the spores germinate, produce mycelium, and aflatoxin is excreted. The mycelium can be removed afterwards by technological processes such as excavating, washing, salting, mixing, drying and heating. Such reasons may account for our findings of 5 ppb aflatoxin B 1 in a sample of mould-free salami and 100 ppb in mould-free ham. Seeds can contain aflatoxins by infection of the egg-cells of the flowering plants. Mould-free peanut kernels isolated from their shell contained 5 and 7 ppb aflatoxin B 1 whilst the more frequently occurring mouldy kernels in the shell contained up to 100 ppb. Mould-free peaches can contain mouldy kernels infected by toxin-producing Aspergilli and Penicillia. Their seeds contained up to 10 ppb aflatoxin B 1 + B 2 + G 1 . During food processing there are many possibilities for mould infection. Blanched almonds for Marzipan and peach or apricot seeds for Persipan should be processed immediately after blanching. We detected 3 ppb aflatoxin B 1 and traces of B 2 and G 2 in blanched almonds kept for 3 days at 28°C. The ready products ‘Marzipan’ (almond paste) and ‘Persipan’ (peach and/or apricot seed paste) can contain aflatoxins in amounts of up to 5 ppb. 55 samples of skim and whole milk powder supplied from 5 different German manufacturers were analysed. The milk powders of one supplier were practically free of aflatoxin M 1 whilst nearly all samples of another supplier contained aflatoxin Mt in amounts ranging from traces to 4 ppb. Pellets for hatched trouts contained 500 ppb aflatoxin B 1 We only detected traces of aflatoxin in the trouts' livers, whilst the faeces contained 500 ppb aflatoxin B 1 Canaries' feed contained 300 ppb aflatoxin B 1 and 125 ppb B 2 . Mouldy corn used as deer fodder contained 25 ppb aflatoxin B 1 and 25 ppb aflatoxin G 1 . Conditions for controlling aflatoxins in stored products and for preventing mould growth and toxin production are discussed. Storage conditions for certain raw materials are mentioned. The results of aflatoxin assays of hundreds of peanut samples harvested in different countries in the last 5 years are intimated.