Impact of takeaway packaging and storage conditions on microbial safety and cereulide production in grilled pork

Delivered ready-to-eat foods have grown increasingly popular in many countries worldwide. Takeaway meals are subjected to transport and storage under variable conditions. This study examined the influence of packaging type (open, semi-open and sealed) and storage conditions (6 °C, 20 °C and 30 °C for 30 min, 2 h and 24 h) on the microbiological safety and quality of grilled pork, with particular focus on cross-contamination from contaminated meat, packaging or side dishes. The total bacterial count of non-inoculated grilled pork continuously remained below the detection limit (0.7 log CFU/g), confirming effective thermal processing before inoculation. Either meat or the packaging surface was inoculated with Escherichia coli, Brochothrix thermosphacta or Yersinia enterocolitica. Furthermore, pasta inoculated with Bacillus cereus was combined with non-inoculated meat. Bacterial growth was significantly influenced by storage temperature, duration and packaging type. Storage at 20 °C and 30 °C, particularly for 24 h, resulted in markedly higher bacterial counts than storage at 6 °C. Semi-open and sealed packaging generally promoted greater bacterial growth and cereulide production than open systems. During storage, cross-contamination of packaging or pasta onto meat was detected. In conclusion, short storage times combined with refrigeration and non-sealed packaging effectively minimized microbial growth and toxin formation. These findings underscore the importance of proper packaging selection and short-term, chilled storage of ready-to-eat foods. This is essential not only to control multiplication of pathogens and spoilage microorganisms, but also to prevent production of stable toxins that cannot be eliminated by subsequent reheating of the food.