Microbial Contamination Dynamics and Source Tracking in Chinese-Style Pork Meatballs: A Cross-Sectional Industrial Study

Chinese-style pork meatballs are widely consumed, yet microbial contamination during processing poses risks to food safety and quality. This study investigated bacterial dynamics and potential contamination sources across seven industrial processing stages of Chinese-style pork meatballs. Culture-based enumeration combined with 16S rRNA gene sequencing revealed a significant decline in total bacterial counts from thawing to cooking ( p < 0.05), demonstrating the effectiveness of thermal processing. Total bacterial counts increased to 3.49 ± 0.00 log 10 CFU/g during the packaging stage, indicating the occurrence of postcooking contamination. This may be primarily attributed to inadequate sanitation and poor hand hygiene. Microbial community analysis showed Chryseobacterium and Acinetobacter were predominant throughout the production chain, while Pseudomonas dominated the packaging stage and final products. Listeriaceae and Weeksellaceae were mainly associated with kneading and thawing stages, respectively. Source tracking indicated that most contamination in final products originated from unidentified sources, reflecting the limitation of SourceTracker when only measured analysis constrained by potential sources is included. These findings highlight critical contamination points in pork meatball processing and provide guidance for targeted hygiene management to improve microbial safety in industrial meat production.