Short communication: Evaluation of spore-former presence in caseinate, cheese and whey powders

This study examined spore-former presence in imported caseinate and the cheese in which it is used as an additive, as well as commercial powders produced from cheese whey (whey protein concentrate-80 (WPC-80) and permeate powder). A single batch of imported caseinate, and the cheese it was utilized in, was collected 11 times over a 16-month period. In addition, samples of commercially produced whey powder were collected over a period of 23 months. Spore-formers were detected using enrichment with reinforced clostridium medium (RCM) in anaerobic conditions and microbiota was analyzed by amplicon sequencing. Gas production was observed in all caseinate samples, with 23 isolates from six known spore-former species identified via matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF). No gas was detected in any of the enriched tubes of the cheese or whey powder samples. We also applied culture-independent analysis to assess microbial diversity and detect spore-formers not identified with the culture-dependent method. Altogether, the results of this study will contribute to the knowledge of spore-former presence and transfer between different dairy products, facilitating targeted actions to reduce quality problems.