Einflu� von K�hltemperaturen auf die Aflatoxin-Entwicklung bei Milchprodukten

Abstract

In the literature several contradictionary results have been published on the aflatoxin formation at temperatures below 10 degrees C. Therefore experiments with pastes made from milk and cheese powder artificially contaminated with Aspergillus parasiticus, were performed at temperatures of 1 degree C, 5 degrees C, and 10 degrees C for 28 days at a relative humidity of 90--95%. Even at 1 degree C, the aflatoxins B1, B2, G1, G2, and M1 could be determined quantitatively. The lactose content did not have a significant influence on the aflatoxin values. Even storage of cheese (camembert and cottage cheese) in a 10% salt solution did not inhibit aflatoxin formation at 20 degrees C.

Experimental aflatoxin production in Manchego‐type cheese

“…In other studies on different types of cheese inoculated with a strain that produces the four main aflatoxins, some authors also found a higher production of G I than of B,. This ratio differed according to the incubation temperature (Lie & Marth 1967;Shih & Marth 1972a;Kiermeier & Behringer 1977a;Polzhofer 1977;Engel 1978;Park & Bullerman 1983a;Karaioannoglou 1984;Zerfiridis 1985). Park & Bullerman (1983b), however, found two to four times more aflatoxin B, than G, secreted by A .…”

“…This represents a high value compared with other authors' findings, although the highest concentration reported has been 800 pg/g in Cheddar cheese portions (Park & Bullerman 1983b). Aflatoxin M, production by aflatoxigenic strains in cheese has seldom been described (Kiermeier & Behringer 1977a, 1977bPolzhofer 19771, probably because of a lack of interest or of the difficulty in detecting it on account of interfering substances, rather than due to a real absence of this toxin.…”

“…This would suggest a possible elimination of these toxins in Manchego-type cheese, as has been observed by other authors in different types of cheese. Kiermeier & Behringer (1977a) reported that aflatoxins may be reduced in cheese even to level 0 throughout ripening. Lie & Marth (1967) found, in Cheddar cheese contaminated with A. juvus, higher levels of aflatoxins during the first week of incubation than in week 7, G, decreasing from 14.4 to 1.9 pg/g, and B from 2.9 to 1.9 pg/g; this only took place in the superficial layer, however, while in the second layer of 0.64 cm values increased due to aflatoxin diffusion.…”