Germany: Fungal toxins in nuts and dried fruits?

In 78 samples of various nut varieties and almonds, as well as 30 samples of dried fruits, examined in the years 2016 and 2017, evidence was found of the fungal toxins aflatoxin and ochratoxin. Particularly notable were sultanas and currants, of which 94% contained low levels of ochratoxin, however in all instances this was below the maximum permitted level of 10 μg per kg. In two samples of ground hazelnuts there were traces of aflatoxin, which also did not exceed official limits.

Analysing for four different aflatoxins and ochratoxins, these were found in amongst others peanuts, Brazil nuts, walnuts, hazelnuts and cashews, besides pistachios. In addition to the aforementioned sultanas and currants, figs and dates were also analyzed and assessed. All samples came from the usual stores, all over the country.

"Whether in Christmas dishes or just something to nibble, nuts are a source of energy with good fats. Almost all contain valuable fatty acids. Dried fruits can be used in a variety of ways as a supplement to baked goods, or they are eaten purely as an energy-rich snack,” says Frerk Feldhusen, Director of the State Office for Agriculture, Food Safety and Fisheries MV in Rostock. Feldhusen: “All nuts and dried fruits which have visible traces of mould -externally or internally- are no longer edible and must be disposed of. If you notice an atypical taste -mouldy, bitter, musty- when eating, you should spit everything out.” An atypical taste does not necessarily indicate moulding, but there is an increased risk.

In order to avoid mould infestation in your own household, nuts and dried fruits should be stored in a cool, dry and airy place.

Though the observed levels were below the official limits, in addition to the establishment of these maximum quantities at European level, regular analyses of nuts and dried fruits are required. Despite intensive efforts to reduce the incidence of mycotoxins in dried fruit, the problem still exists, although the study showed a trend towards improvement this year. Routine checks remain crucial to ensure effective consumer protection.

Nuts can already be attacked by fungi on the tree, but also during transport or storage, due to humidity and heat. These factors can lead to the development of poisons (mycotoxins). The fungal toxins are invisible to the naked eye and are not recognizable by smell or taste. The special kind of mycotoxins, the aflatoxins, are heat and acid stable. They will therefore survive the usual food processing and preparation methods and can still be found in roasted nuts.

Aflatoxins are also mycotoxins. Mycotoxins are naturally occurring, so-called secondary metabolic products of mould fungi. Aflatoxins are formed, among others, by the mould fungi Aspergillus flavus and Aspergillus parasiticus. In humans, they can promote the development of cancer, damage the kidneys and liver, impair the immune system or cause diarrhea and vomiting. In addition to this, aflatoxins can damage the human genetic material, that is they have a genotoxic effect.

Ochratoxins are created via inadequate storage conditions, especially with high levels of humidity. This fungal toxin can also cause kidney and liver damage, is classified as potentially carcinogenic for humans and is also genotoxic. The problem is its long half-life in the animal and human organism, ie after consumption of contaminated products the toxin is metabolized and excreted from the body only very slowly.

Source: lallf

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