Exploring food spoilage: an inquiry-based laboratory for food microbiology education

Proper maintenance of the cold chain is essential to ensure both food quality and safety. This laboratory activity was designed to help undergraduate students understand the microbiological implications of cold chain failure through direct microbiological analysis and data interpretation on commercial foodstuffs. We designed an inquiry-based laboratory activity for final-year undergraduate students at the University of Milan (Milan, Italy) to explore the effects of thermal abuse on microbial populations in turkey hamburgers and ready-to-eat salads. Students analyzed key microbial groups, including aerobic mesophilic bacteria, lactic acid bacteria, yeasts, fungi, <i>Pseudomonas</i> spp., <i>Escherichia coli</i>, <i>Enterococcus</i> spp., staphylococci, and presumptive <i>Bacillus cereus</i>, under controlled and temperature-abused storage conditions. They classified samples according to microbial load and compared their results to food microbiology guidelines to assess their quality. Survey feedback revealed student engagement, with over 85% recognizing the activity's relevance to their future careers and its impact on critical thinking. This inquiry-based laboratory promotes food quality learning by integrating microbiological techniques with real-world challenges, strengthening students' appreciation for the role of food scientists and technologists in preventing risks to public health.