Detection of Animal Products in Ruminant Feeds by Microscopy and Real Time PCR

Abstract

This study evaluated the performance of the TaqManTM real-time PCR assay to detection of DNA from not allowed-animal derivatives in reference feeds samples. The results of qPCR were compared with the microscopy, only method validated to control the presence of animal proteins, according the European Communities. The qPCR tests targeting 12S rRNA from cows, sheep, porcine and chickens and cytochrome b region from caprine in feeds were able to detect half the amount (0.0125% w/w) of meat-and-bone meal (MBM) that could be detected by microscopy in samples spiked with MBM. Although cross-contamination in feeds and food processing plants is an unexceptional problem, the presence of traces of prohibited animal products in feedstuffs is an alert to potential impact on herd and human health, because it has been associated with the transmission of transmissible spongiform encephalopathy (TSE). These results indicate that a combination of qPCR tests and microscopic analysis could be used to ensure the safety of feedstuffs, allowing the identification of the animal species of the derivative and even the kind of tissue added to the feed, providing useful information for sanitation inspection authorities in this country.