Lowering of ochratoxin A level in milk by yoghurt bacteria and bifidobacteria.

A decrease in the content of ochratoxin A (OA) was observed in milk samples fermented by yoghurt bacteria and bifidobacteria. OA was added to the milk before fermentation at a rate of 0.05-1.5 mg/L. No residues of OA were found in samples containing 0.05 and 0.1 mg/L of OA, fermented by S. Salivarius subsp. thermophilus, L. delbrueckii subsp. bulgaricus and B. bifidum. Yoghurt bacteria (S. salivarius subsp. thermophilus and L. delbrueckii subsp. bulgaricus) were the most effective since no residues were detected even in fermented samples containing originally 0.5 mg/L OA.

Contamination of broiler chicken's mash and litter with moulds, aflatoxins, ochratoxin A and zearalenone.

Contamination of broiler chicken's mash and litter with moulds, aflatoxin B1 (AB1), G1 (AG1), ochratoxin A (OA) and zearalenone (F-2 toxin) was examined on a broiler fattening farm. All broiler chicken's mash samples tested were contaminated with moulds. The highest total viable counts of moulds (3.3 x 10(5) per g) were found in broiler starter diet. Moulds isolated from mash were classified into 8 genera and 27 species. Many of them (Aspergillus spp., Fusarium spp., Penicillium spp.) are known as mycotoxin-producing moulds. Fusarium moniliforme was the dominant species in mash mycopopulations. Moulds were also found in all litter samples. The highest fungus count (80 x 10(5) per g) in litter was found at the beginning of fattening. Fungi isolated from litter samples belonged to 9 genera and 22 species. Aspergillus, Penicillium and Mucor were the most prevalent genera. None of the broiler chicken's mash and litter samples tested was contaminated either with AB1, AG1, OA or with F-2 toxin. F. moniliforme was zearalenone-negative also under laboratory conditions.

Interactive effects of propionic acid and temperature on growth and ochratoxin a production by Penicillium aurantiogriseum.

Propionate at concentrations up to 0.05% decreased at 25 degrees C the growth and sporulation of Penicillium aurantiogriseum. The standard size of conidiogenous structures (metulae, phialids) and conidia was diminished. The effect was more pronounced at a higher temperature (30 degrees C). Inhibition of ochratoxin production by propionate was also demonstrated.

Occurrence of Fusarium species and zearalenone in dairy cattle feeds in Vojvodina.

The occurrence of Fusarium spp. and zearalenone (F-2 toxin) in dairy cattle feeds was studied during a period of three years (in all seasons) in Vojvodina. Fusarium species were found to be very common in feeds. They were classified into 11 different species (F. chlamydosporum, F. equiseti, F. flocciferum, F. graminearum, F. lateritium, F. moniliforme, F. oxysporum, F. semitectum, F. solani, F. tabacinum and F. tricinctum). Some of these species are known to produce mycotoxins. The highest distribution of Fusarium spp. was observed in the autumn and spring of the second research year, when 53 and 56% of the feed samples, respectively, were contaminated with them. F. oxysporum and F. moniliforme were the most prevalent species throughout the three-year study. Zearalenone was found in various feed samples at concentrations between 140.00 and 960.00 micrograms/kg in all seasons, except in the summer of the first year, in the winter of the second year and in the autumn of the third research year. Pelleted sugar beet pulp and pelleted malt spent grains were the feeds most contaminated with this toxin. Thirty-five out of the 275 feed samples contained zearalenone and 11 of them were contaminated with zearalenone-producing moulds and zearalenone at the same time.

Ochratoxigenic moulds and ochratoxin A in forages and grain feeds.

The contamination of forages and grain feeds with ochratoxigenic moulds and ochratoxin A was examined. The investigations were carried out over a period of three years in all seasons. Feeds were found to be contaminated with moulds at a high level throughout the three research years. The highest percentage (95 to 100) of contaminated feed samples was noticed during the second year. Total viable counts of moulds established in 1 g of feed samples ranged from 0.5 to 7.8 x 10(6). Penicillium spp. were dominant in mycopopulations isolated from feeds. Ochratoxin-A producing moulds were present permanently. In the summer period of the second research year as much as 94% of the feed samples were contaminated by ochratoxigenic Penicillium species. P. verrucosum var. cyclopium P. verrucosum var. verrucosum, P. commune and P. chrysogenum, i.e. ochratoxin-producing moulds, were the most prevalent Penicillium species throughout the three-year investigation. Ochratoxin A was found in various feeds in all seasons, except in summer of the first research year. Concentrations of the toxin varied from traces to 400 micrograms/kg. It occurred consistently in the same types of feeds (hay, dried alfalfa, fresh alfalfa, concentrate, pelleted sugar beet pulp, corn silage).

Distribution of aflatoxin-producing moulds and aflatoxins in dairy cattle feed and raw milk.

Distribution of aflatoxigenic moulds and aflatoxin B1 in Yugoslav dairy cattle feeds as well as the presence of aflatoxin B1 and M1 in raw milk, was tested. The experiments were carried out through three years (in all seasons). Samples were taken from state and private farms in Vojvodina. Feeds were contaminated in 83-100% with moulds. Fungi of farms in Vojvodina. Feeds were contaminated in 83-100% with moulds. Fungi of Aspergillus flavus-oryzae group were present permanently and the highest incidence of them was noticed during the third research year. Aflatoxin B1 was not found in the first year, but malt spent grains used for cows' feeding in summer of the second research year was contaminated with it (50.0 micrograms/kg). The same feed and pelleted sugar beet pulp were contaminated with aflatoxin B1 in winter, spring and summer of the third research year (5.0 to 16.0 micrograms/kg). Aflatoxin B1 and M1 were not found in raw milk through three-years investigations.

Ochratoxigenicity of Aspergillus ochraceus group and Penicillium verrucosum var. cyclopium strains on various media.

Production of ochratoxin A (OA) by strains of Aspergillus ochraceus group (A. ochraceus--21, A. sclerotiorum--1, A. sulphureus--1) and Penicillium verrucosum var. cyclopium strains--11, on various media was investigated. Thirteen percent of A. ochraceus strains and 18% of P. verrucosum var. cyclopium formed OA growing on sterile crushed wheat for 14 days at 25 to 27 degrees C (preliminary experiments). Toxin concentrations were 5.0 to 7.0 micrograms/kg. Five strains OA-positive on crushed wheat and four OA-negative strains were cultivated on various liquid nutritional media (YES, RM, OAT, CG and AFP). All the strains tested, including OA-negative ones, produced OA on certain liquid media. Concentrations of OA were low again (trace to 16.0 micrograms/l). The largest number of mould strains examined produced OA on YES (55.5%) and RM media (44.0%), but the highest concentration (16.0 micrograms/l) was formed on YES and CG media.

Decrease of aflatoxin B1 in yoghurt and acidified milks.

Fermentation of yoghurt and acidified milks containing aflatoxin B1 (AB1) were studied. AB1 added to milk before fermentation at concentrations of 600, 1000 and 1400 micrograms/kg was reduced in yoghurts (pH 4.0) by 97, 91 and 90%, respectively. Coagulation time was approximately the same as in the controls. Streptococci had longer chains than those in the controls. The main decrease of AB1 occurred during the milk fermentation. A decrease of AB1 (conc. 1000 micrograms/kg) in milks acidified with citric, lactic and acetic acids (pH 4.0) was 90, 84 and 73%, respectively.