In this study, two methods for assessing the purity of A2 fermented milk and β-casein genotypes in dairy cows were examined. The need for rapid and precise methods for herd screening and A2 milk quality control justified this study. Accordingly, an ELISA test was developed to identify β-casein A1 in fermented milk, and a commercial Lateral Flow Immunoassay (LFIA) was evaluated to determine A2A2 genotypes and the purity of A2 milk. The results demonstrated 100% sensitivity and specificity of the ELISA test in identifying β-casein A1. The LFIA test successfully identified A2A2 genotypes and confirmed the purity of A2 milk, with a minimum detectable contamination of 5% for raw milk and 10% for fermented milk. Both tests exhibited 100% sensitivity and specificity, resulting in positive and negative predictive values of 100%. The positive likelihood ratio was infinite, while the negative was zero, indicating a precise and reliable test with no false diagnoses. Compared to traditional genotyping, these methods proved to be more practical and showed potential for large-scale screening. It was concluded that ELISA and LFIA are valuable tools for ensuring the quality and authenticity of A2 milk, meeting the demands of producers and consumers for safe and healthy dairy products.
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