Aflatoxin M1 in Milk

Aflatoxins are toxic metabolites produced by a variety of molds such as Aspergillus flavus and Aspergillus parasiticus. They are carcinogenic and can be present in grains, nuts, cottonseed and other commodities associated with human food or animal feeds. Crops may be contaminated by one or more of the four following sub-types of aflatoxin: B1, B2, G1 and G2. While the other sub-types of aflatoxin present a significant danger at high concentration levels, aflatoxin B1 is the most toxic and frequently detected form.

Aflatoxins have been implicated in human health disorders including hepatocellular carcinoma, aflatoxicosis, Reye’s syndrome and chronic hepatitis. Animals are exposed to aflatoxins by consumption of feeds that are contaminated by aflatoxin-producing fungal strains during growth, harvest or storage. When cows are fed contaminated feed, aflatoxin B1 is converted by hydroxylation to aflatoxin M1, which is subsequently secreted in the milk of lactating cows. Aflatoxin M1 is quite stable towards the normal milk processing methods such as pasteurization and if present in raw milk, it may persist into final products for human consumption.

Most controlling government agencies worldwide have regulations regarding the amount of aflatoxins allowable in human and animal foodstuffs. Many countries have declared limits for the presence of aflatoxin M1 in milk and milk products. In the EU the limit for the presence of M1 in milk and reconstituted milk powders has been set at 0.05 mg/L or 50 parts per trillion (50 ppt.)

In response to the EU’s growing demand for stringent regulation of aflatoxin M1 in milk products, Helica Biosystems has created quantitative ELISA assays for the detection and quantization of aflatoxin M1 in milk, reconstituted milk powders and cheese. Detection of aflatoxin M1 is a simple process, with just a single dilution step and no complicated extraction.

Recovery and Reproducibility

Recovery of 50 ppt spiked into milk is as follows:

	% Recovery	Within Assay CV
SKIM MILK 50 ppt	100	4.2%
1% FAT HOMOGENIZED 50 ppt	93	4.4%
FULL FAT HOMOGENIZED 50 ppt	92	2.2%

Recovery in cheese: 100 pg of aflatoxin M1 was spiked into 1 gm of finely grated parmesan cheese and allowed to remain in contact for one hour at ambient temperature. Applying the extraction procedure described above, the recovery of aflatoxin M1 was 60.5% with a CV of 5.5% for 8 separate spiking/extractions.

Performance Data

Sensitivity