Identification of volatile spoilage indicators for pork packaged under modified atmospheres

Aim: Modified atmospheres have been widely implemented in the domain of meat packaging to prolong shelf life. However, pork is still highly susceptible to microbial activity. Over storage time, specific spoilage organisms can use nutrients rapidly and generate volatile organic compounds (VOCs) characterized by unpleasant odors. The aim of this study is to identify VOCs that contribute to pork spoilage in modified atmosphere packaging. Method: In this study, fresh pork was packaged under different gas mixtures (%O2/CO2/N2): air, 70/30/0, 0/30/70. Meat quality during the 4 °C storage was characterized by classic microbiological analysis, sensory evaluation and real-time mass spectrometry (selected-ion flow-tube mass spectrometry, SIFT-MS). The obtained datasets were subsequently analyzed by using multivariate statistics for the identification of potential spoilage indicators. Results: While air packaging favored the growth of Pseudomonas spp., the decreased level of oxygen (0/30/70) and/or the addition of CO2 (70/30/0) inhibited the growth of aerobic pseudomonads and supported the growth of lactic acid bacteria over other species. Statistical analysis results revealed a positive correlation between the spoilage volatilome, bacterial growth and the increased percentage of sensory rejection. Acetoin was one of the most significant spoilage markers under aerobic conditions, whereas ethanol, 3-methylbutanal and sulfur compounds can indicate the progress of anaerobic spoilage. Conclusion: This study has provided deep insights into the volatolomic profiles during meat spoilage under different packaging conditions. Monitoring the levels of these spoilage-related compounds can be promising for predicting quality deterioration in the early or intermediate storage stages. Thus, the results can be expected to be useful when aiming at developing novel methods for safeguarding food and reducing spoilage wastage in the supply chain