2.2.2. Purification
Immunoaffinity columns were used to purify AFB1, AFB2, AFG1 and AFG2.
The raw milk was collected directly from milk-holding tanks at milk stations on the dairy farms. After stirring the milk-holding tank, each 200 mL of milk was taken from the upper third, the middle third and the lower third of the tank, respectively. The total 600 mL of milk from each tank was mixed, from which a 100 mL sample was taken and stored at 20 C until the analyses were performed. Feed samples were collected from sacks, which were selected randomly, with each 2 kg of feed taken from the upper third, the middle third and the lower third of each sack. The total 6 kg of feed was mixed, from which 0.5 kg of the sample was collected and heated at 65 C to remove moisture. It was then stored at room temperature until analysed.