アフラトキシン M₁ 自然汚染乳と人工汚染乳を用いた乳製品のアフラトキシンM1 の濃縮価

抄録

Aflatoxin M₁ (AFM₁) is a mycotoxin which frequently contaminates milk and dairy products. AFM₁ is known to be transferred into dairy products, such as cheese, cheese whey, and butter from milk. A number of transfer tests of AFM₁ into cheese have revealed that AFM₁ is transferred and enriched at a specific ratio (enrichment factor [EF]: concentration of AFM₁ in dairy product/ concentration of AFM₁ in milk) that varies depending on the kind of cheese. However, few reports have so far investigated the differences regarding types of contamination in raw milk (e.g. naturally or artificially contaminated) on the EF of the cheese. We examined the effect the contamination situation on the EF in Gouda cheese, which is the most produced natural cheese in Japan. The cheese was made from milk either naturally or artificially contaminated with AFM₁, and the concentration of AFM₁ was analyzed using a validated sensitivity method which we recently developed. The EF of Gouda cheese made from milk artificially contaminated with AFM₁ at 0.5, 1.0, and 2.0 μg/L was calculated as 2.80, 3.06, and 2.68, respectively, while that made from milk naturally contaminated with AFM₁ at 0.49 μg/kg was 5.01. The EF of cheese whey was 0.60, 0.60, and 0.55 in milk artificially contaminated with AFM₁ at 0.5, 1.0, and 2.0 μg/L, respectively, and 0.53 in the naturally contaminated milk. Significant differences were noted in the EFs of the products from the naturally and artificially contaminated milk. This study was the first to demonstrate that EFs obtained from both naturally and artificially contaminated milk in Gouda cheese. Additionally, the EF of butter was examined using only the milk artificially contaminated with AFM₁ at 0.5, 1.0, and 2.0 μg/L. The EFs ranged from 0.12- 0.34, indicating that AFM₁ was not enriched in the butter.