Characterization of microorganisms following dairy keeping quality tests in Québec

Despite best efforts of the dairy industry, premature spoiling and non-compliance of products remain problematic and cause economic loss. In this study, 190 dairy products/samples of the Québec province were analyzed using governmental quality tests and keeping quality tests, such as the Virginia Tech. procedure, the Moseley test and a Paenibacillus test, to allow identification, by 16S sequencing, and characterization of the microorganisms causing non-compliance. We found that the Paenibacillus test isolated mostly Bacillus and Paenibacillus whereas the other tests isolated primarily Pseudomonas . Tests in 96-well assay plates showed that Pseudomonas had the most moderate to strong biofilm forming ability producers. Except for four isolates of Pseudomonas and one isolate of Stenotrophomonas chelatiphaga , biofilm producers were sensitive to both sodium hypochlorite and peracetic acid at concentrations typically used to disinfect dairy equipment. This study will help in the development of control strategies targeting problematic bacterial contaminants in the dairy sector. • Collection of microorganisms causing non-compliance or spoilage in dairy products • Isolated from keeping quality tests such as the Moseley, Virginia or Paenibacillus • Identified by 16S sanger sequencing include Pseudomonas , Paenibacillus , Bacillus • Assessment of their biofilm forming ability using 96 well microplate method • Disinfectant sensitivity assed by MBEC for sodium hypochlorite and peracetic acid • Relationship analysis using a logistic model between tests and products