Pakistan milk supply chain under the peril of mycotoxins.

Byline: Naveed Akbar

Mycotoxins are a family of toxins produced by certain fungi. There are three main types of mycotoxins that produce toxins are Aspergillus, Fusarium, and Penicillium, which are abundant in warm and humid regions of the world. Aspergillus produce toxin which are more abundant and known as Aflatoxin. These fungi can contaminate crops in the field, at harvest, and during storage. According to the Food and Agriculture Organization (FAO), one forth of the world's crop is affected by aflatoxins. Aflatoxins are a group of hepatotoxic, carcinogenic and immunosuppressive fungal metabolites. International Agency for Research on Cancer has classified aflatoxins B1, B2, G1, G2 and M1 as group 1 carcinogen. Aflatoxin B1 is the most toxic compound and it is one of the biosynthetic precursors of the other aflatoxins.

When lactating mammals such as cows, sheep and goat are fed with AFB1 contaminated feed, the ingested AFB1 is converted to AFM1 by hydroxylation at the tertiary carbon of the difuran ring system, metabolized by cytochrome P450 enzyme system in the liver. About 0.30 to 6.2% of AFB1 in animal feed is transformed to AFM1 in milk. The transformation rate may vary from animal to animal. The AFM1 starts appearing in milk approximately after 12 to 24 h of the first AFB1 ingestion.

Aflatoxins are a worldwide threat to public health and economy and therefore, extensive surveillance on the levels of aflatoxins B1, B2, G1, G2 and M1 has been conducted throughout the world including developing countries like India and Pakistan. The presence of aflatoxin M1 in milk and dairy products makes it a particular risk for humans because these products are largely consumed by children including infants who are considered more susceptible to the adverse effects of AFM1. More than 60 countries have set maximum permissible level for AFM1 in milk.

Pakistan is the fifth largest milk producer in the world with an approximately 29 million tons annual production. Milk in Pakistan is mainly produced by small farmers at small scales. Feed storage conditions in small scale farms are often not satisfactory due to economic backwardness of the producers and would not reduce the occurrence of the mycotoxins in the feed or the milk. Most milk (70%) in Pakistan is produced by buffalo. About 98% of the milk is sold in raw form with only 2% going to processing. A significant portion of milk is converted into dairy products. Among the dairy based products, mithae...