Hands-on learning for probiotic quality assessment: enhancing microbiology education through applied microbial counting techniques

The microbial plate count continues to be an essential technique in food microbiology research and quality control. In food science education, this technique is often taught through traditional fact-based methods, requiring students to follow pre-established protocols. This approach may not fully engage students or enhance their problem-solving skills. Eighty-two final-year Food Science and Technology bachelor's students at the University of Milan were asked to combine their knowledge on general microbiology and microbial physiology for quality assessment of different probiotic products, including freeze-dried cells, fermented milk, and bacterial spore suspension. They were required to select the appropriate culture media, incubation conditions, and treatments based on flow cytometry cell quantification to optimize microbial plate counts and selectively count the different microbial species present in the probiotic formulations. The project aimed to bridge theoretical knowledge with practical applications, emphasizing the most appropriate procedure for viable and cultivable cell quantification, particularly relevant in probiotic formulation. Survey feedback indicated high satisfaction and relevance to future careers, with the majority finding the activity challenging yet engaging. The project demonstrated the effectiveness of combining different microbiological techniques in education, fostering a deeper understanding of the cultivability of probiotics and the role of selective agents.