Developing real-time monitoring methodologies for evaluating pork spoilage under modified atmospheres

Pork is one of the most appreciated and yet simultaneously most perishable meat products. Over storage time, microbial behavior is the main reason for the production of volatile organic compounds (VOCs), the emission of unpleasant off-odors and eventually sensory rejection. Thus, it is regarded as highly promising to monitor the levels of these spoilage-related compounds in a faster manner when considering improving meat quality control. Moreover, quantitative information on VOC generation during storage is important for development of spoilage indicating sensors. However, information concerning the pork volatilome is still limited in the scientific literature. In this study, fresh pork was stored at 4°C under air and 70%O2/30%CO2. Meat quality was assessed by using real-time mass spectrometry via selected-ion flow-tube mass spectrometry (SIFT-MS) and classic microbiological analyses. In the used methodologies, 48 product ions were selected to quantify VOCs based on preliminary qualitative scanning and literature survey. Air storage favored the growth of aerobic Pseudomonas spp. High-O2 packaging with addition of CO2 slowed down the Pseudomonas growth and lactic acid bacteria became the predominating microorganisms. Due to evident accumulation in the late storage, ethanol, 3-methylbutanal, acetoin, sulfuric compounds and other VOCs have the potential as spoilage markers. Twenty VOCs that showed significant increase over time (p < 0.05) can be further used for pork quality monitoring. The introduction of SIFT-MS has accelerated spoilage recognition and can be expected applicable in many food supply scenarios