Method development and validation for detection of bar gene encoding phosphinothricin N-acetyl transferase in milk-based products using real-time PCR technique

Transferring herbicide resistance genes to crop varieties is one of the most effective methods to control weed growth on agricultural land. The bar gene isolated from Streptomyces hygroscopicus was found to confer glufosinate resistance to crops. This gene encodes the enzyme phosphinothricin N-acetyltransferase (PAT), which is capable of inactivating phosphinothricin-containing herbicides (PPT) by promoting the acetylation of glufosinate ammonium, the main active ingredient in many herbicides. The most common genetically modified crops are soybeans, corn, rice, and cotton. Soybeans and corn are also the main crops used in processed foods. In this study, the authors applied a standardized real-time PCR method issued by the European Commission to detect the bar gene in milk products, including soy milk, corn milk, and fresh milk. The method is based on the amplification of the bar gene, showing high sensitivity with a detection limit of 0.05%, while achieving 100% specificity and accuracy.