Effect on Aflatoxin Formation of Different Storage Conditions in Tulum Cheese inoculated with Aspergillus parasiticus NRRL 2999


Abstract: Tulum cheese was divided into 2 equal parts. One part was inoculated with 10^4 spores/g of aflatoxin-producing Aspergillus parasiticus NRRL 2999 strain. The other part, the control group, was not inoculated. All the samples were ripened in glass jars at 2 different temperatures (10 ± 1 and 20 ± 1 °C) and relative humidities (85 ± 2% and 95 ± 2%) and analyzed for aflatoxin formation on days 1, 15, 30, 45, 60 and 90 of storage using thin layer chromatography. Aflatoxins were determined in the inoculated samples after 15 days with incubation at 20 ± 1 °C, while they were not found in inoculated samples stored at 10 ± 1 °C or in any of the control group samples during a ripening period of 90 days. The levels of aflatoxins decreased after 15 days of storage. In 85 ± 2% and 95 ± 2% relative humidities, the levels of aflatoxins were 0.98 µg/kg B_1, 47.90 µg/kg G_1 and 4.20 µg/kg G_2; and 32.76 µg/kg B_1, 118.80 µg/kg G_1 and 51.98 µg/kg G_2 at the end of 90 days, respectively. The level of aflatoxin B_2 was 47.25 µg/kg and 60.50 µg/kg in 85 ± 2% and 95 ± 2% relative humidities at the end of 30 days, respectively. However, it was not determined on days 45, 60 or 90. Data obtained in this study indicated that storage time and temperature, humidity and aflatoxigenic mould contamination significantly affected aflatoxin formation in Tulum cheese. It was concluded that aflatoxin did not form in Tulum cheese stored at

Keywords: Tulum cheese, aflatoxin, Aspergillus parasiticus, relative humidity, storage temperature

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