Screening of aflatoxin B1 in laboratory rat feed

Many hazards can interfere with the safety of the feeding stuffs intended to provide nutrients to experimental animals. Chemical and biological contaminants of laboratory animal feed can be a problem for toxicological and immunological research. Aflatoxin B-1 (AFB(1)) is a secondary toxic metabolite, produced by the ubiquitous fungal genera, Aspergillus. AFB(1) is particularly dangerous for health, inducing cancer of the urinary tract or liver carcinoma. The aim of this preliminary screening was to evaluate the presence of AFB(1) in 31 samples of laboratory rat feed using a method validated in-house, then separated by High Pressure Liquid Chromatography (HPLC) coupled to a fluorescence detector. The detection limit (limit of detection: LOD) and the quantification limit (LOQ) were 0.2 and 0.4 mu g/kg respectively. Recoveries ranged from 58.0 to 74.5% for spiked samples. The immunoaffinity approach was significantly faster than methods employing conventional chromatography clean-up (Sep-Pak Classic Florisil and Sep-Pak ClassicC(18) cartridges). Aflatoxins were not detected in any analysed sample.