# Analysis of Potential Markers of Pork Freshness Based on Volatile Organic Compounds
## 1 Introduction  
Pork is the most widely consumed meat per capita worldwide, according to data from the US Department of Agriculture's Foreign Agricultural Service [1]. Its popularity among consumers is due to its abundance of high-quality protein and other nutrients [2, 3, 4]. However, microbial activity and lipid-protein oxidation make pork extremely perishable [5]. These processes can lead to changes in color and texture, slime formation, and the emergence of unpleasant odors [6, 7].  
At present, total volatile basic nitrogen (TVB-N) and total viable count (TVC) are extensively employed in laboratories to evaluate the freshness of pork [8, 9, 10]. Although these methods are highly accurate and reliable, they are time-consuming and labor-intensive, making them unsuitable for real-time monitoring [11]. In recent years, spectroscopic methods such as near-infrared (NIR) and Raman spectroscopy have become popular due to their precision and speed in assessing meat freshness [11, 12, 13, 14, 15]. A multivariate statistical information fusion method utilizing NIR spectroscopy has been employed to create quantitative predictive models for TVB-N and pH to evaluate pork freshness [11]. A TVC predictionalgorithm utilizing hyperspectral imaging technology has been implemented for the non-destructive detection of chilled pork [17]. These non-invasive techniques provide the swift detection of chemical and biological alterations in meat products, delivering real-time and precise food safety data to regulators. Nonetheless, their intricacy and the specialized knowledge necessary for their utilization restrict their broad adoption among consumers.  
Gas chromatography-mass spectrometry (GC-MS) is extensively utilized for the identification and quantification of volatile organic compounds (VOCs) [17; 18; 19]. The generation of off-flavors during meat deterioration is attributed to specific VOCs [20]. Consequently, GC-MS is employed to detect VOCs that indicate changes in meat freshness, offering a novel methodology for assessing pork quality. [PERSON] et al. utilized correlation analysis and multivariate statistics to identify signs of deterioration in beef [21]. [PERSON] and colleagues employed thermal desorption gas chromatography-mass spectrometry (TD-GC/MS) to detect signs of deterioration in chicken breasts stored in modified environment packaging at 6 \({}^{\circ}\)C [22]. Additionally, [PERSON] et al. used HS-SPME-GC-MS and correlation analysis to find possible volatile indicators of spoilage in pork [23]. [PERSON] et al. investigated the release of VOCs in pork stored in modified atmosphere packaging at 4 \({}^{\circ}\)C, although they did not focus on identifying specific spoilage indicators [24].  
This study aims to quantitatively analyze the changes in VOCs during pork storage using HP-SPME-GC-MS. Specific VOCs associated with spoilage will be identified to provide a scientific basis for pork quality control. Furthermore, a dynamic indicator for quality monitoring throughout the storage process is proposed, which is expected to enable the real-time tracking and evaluation of pork quality.