Epsilon Archive for Student Projects

Abstract

The increasing demand for plant-based products in the Swedish market has raised concerns regarding the potential presence of Listeria monocytogenes, a pathogenic bacterium, in ready-to-eat products such as plant-based deli slices. Compliance with current legislation requires assessing a product's ability to support or inhibit the growth of L. monocytogenes. Therefore, this study aimed to investigate the growth potential of L. monocytogenes in vegan salami.
The "challenge test" method was employed to evaluate the growth potential. Vegan salami samples were inoculated with two strains of L. monocytogenes and stored at 8°C for approximately 30 days. The concentration of L. monocytogenes was measured at the beginning, three intermediate time points, and at the end of the test. Prior to inoculation, a qualitative method was used to detect the initial presence of L. monocytogenes. Physicochemical characteristics were also assessed during the challenge test, and non-inoculated samples were analyzed for the same characteristics and total bacterial count.
The results indicated varying growth among the three different batches (with different production dates), with L. monocytogenes levels increasing from an initial inoculation level of 2 log10 to 7 log10 cfu/g during the challenge test. The overall growth potential across all batches was 4.4 log10 cfu/g. Furthermore, the physicochemical characteristics showed a decrease in pH, an increase in CO2 levels (especially for Batch 2), and varying concentrations of total bacterial count (TBC). In conclusion, these findings demonstrate that vegan salami has the potential to support the growth of L. monocytogenes. To comply with existing legislation, it is crucial to ensure the absence of L. monocytogenes in 25 grams of the product upon leaving the manufacturer.