Assessment of four different DNA extraction methodologies for the molecular detection of phage λ and Bacillus sp. in raw bovine milk samples

Microbiological analysis of milk is essential to guarantee the quality and safety of dairy products. Molecular methods based on identifying nucleic acids, such as PCR, detect a diversity of microorganisms; however, inhibitors such as fats make milk a complex matrix for extracting DNA. In this study, different DNA extraction methodologies were compared for the molecular detection of microorganisms in raw bovine milk samples, evaluating performance through the concentration (ng μL⁻¹) and purity (index 260/280) of the DNA extracted from each milk sample by spectrophotometry, gel electrophoresis, and PCR amplification. The results demonstrated that the commercial QIAamp DNA mini kit method is significantly better when compared with MagMAX™ Viral/Pathogen Nucleic Acid Isolation Kit Thermo Scientific ™, salting out, and Chelex™ 100 in terms of concentration and quality.