Impact of feed characteristics for monitoring AFB1 contamination in commercial concentrate feeds used in small holder dairy farms, Chiangmai, Thailand

Abstract

The objective of this study was to determine the impact of abnormal physical characteristics for monitoring
aflatoxin B1 (AFB1) contamination in commercial dairy concentrate feeds. The study was conducted during March to
May 2013 using 82 dairy farms in Chiang Mai province, Thailand. All feed samples were collected from new packages
and their physical characteristics were subsequently determined. AFB1 concentrations in the samples were measured
using the enzyme-linked immunosorbent assay (ELISA), and feed samples with AFB1 of more than 5 µg/Kg were
determined as AFB1 contaminated samples. The impact of physical characteristics on AFB1 contamination were
evaluated using a multiple logistic model with a p-value less than 0.05. Forty percent (39 of 97) of the feed samples
were contaminated with AFB1. Concentrate feeds with rancid or sour odors had a higher risk of AFB1 contamination
(OR =4.79, P=0.03), as did samples with a high appearance of a brightly illuminated fluorescence on feed after testing
with black light (OR= 24.04, P = 0.0002). Farmers can use these indicators as screening tests before purchasing the feed.