RESUMEN
BACKGROUND: With increasing media coverage of food safety incidents, such as that of clenbuterol residues in pork, food safety has become a major public health concern in China. Rapidly developing online markets attract increasing numbers of Chinese consumers to purchase food on the Internet. However, the quality and safety of food sold online are uncertain and are less reported on. OBJECTIVE: This research aimed to systematically study the quality and safety of chilled pork from wet markets, supermarkets, and online markets in China. RESULTS: The chilled pork samples from online markets were fresher than those from wet markets and supermarkets based on the surface redness (a* value). Chilled pork contained high levels of nutritional elements, especially the magnesium and phosphorus levels in samples from online markets. The levels of heavy metal element residues and veterinary drug residues in all chilled pork samples were within the standards limits. In addition, huge differences existed in the quality and freshness of the chilled pork samples from online markets according to principal component analysis (PCA). CONCLUSIONS: Most chilled pork sold in Chinese markets was qualified and safe. It is necessary to establish an effective online market supervision system for chilled pork.