Isolation and identification of fungi associated with feed stuffs and determination of mycotoxin producing ability

A general survey was carried out during the period 1987 / 88 on the microflora associated with animal feedstuffs collected from different factories in east Alger. A total number of 139 fungal isolates were obtained and classified in 12 different genera, namely: Alternaria, Aspergillus, Cladosporium, Cordana, Cunning/lamella, Fusarium, Gliocladium, Mycotypha, Penicillium, Pythium, Rhizoctonia, Rhopalomyces. Aspergillus isolates were found most widely distributed in the samples. They were 68.3% of the total isolates obtained. Aspergillus ochraceus was 36.8% of the Aspergillus isolated and 25% of the total fungal isolates. Isolates were tested for their ability to produce antibiotics in culture media. All were capable of producing different levels of toxins active against gram positive and gram negative bacteria. Subsequent investigations have revealed that the majority of fungal organisms included in the genera Aspergillus and Penicillium are able to produce ochratoxins

Production of ochratoxin A in a semisynthetic medium

Seven Aspergillus and two Penicillium strains were tested for the production of ochratoxin A and B. The isolates were grown on Czapek liquid medium supplemented with varying amounts of sucrose [0-4%]. All of the isolates were capable of producing different levels of ochratoxin A in nutrient medium containing 4% sucrose and 2% yeast extract after 13 days of incubation at 28° as static cultures. Aspergillus ochraceus produced up to 31.36mg/100ml of ochratoxin A and trace amount of ochratoxin B under these conditions. The Penicillium strains produced less ochratoxin A than A. ochraceus