In recent years, the prevalence of pseudorabies virus (PRV) has caused huge economic losses to the Chinese pig industry. Meanwhile, PRV infection in humans also sounded the alarm about its cross-species transmission from pigs to humans. To study the regional PRV epidemic, serological and epidemiological investigations of PRV in pig populations from Yunnan Province during 2017–2021 were performed. The results showed that 31.37% (6324/20,158, 95% CI 30.73–32.01) of serum samples were positive for PRV glycoprotein E (gE)-specific antibodies via enzyme-linked immunosorbent assay (ELISA). The risk factors, including the breeding scale and development stage, were significantly associated with PRV seroprevalence among pigs in Yunnan Province. Of the 416 tissue samples collected from PRV-suspected pigs in Yunnan Province, 43 (10.33%, 95% CI 7.41–13.26) samples were positive for PRV-gE nucleic acid in which 15 novel PRV strains from these PRV-positive samples were isolated, whose gC and gE sequences were analyzed. Phylogenetic analysis showed that all 15 isolates obtained in this study belonged to the genotype II. Additionally, the gC gene of one isolate (YuN-YL-2017) was genetically closer to variant PRV strains compared with others, while the gE gene was in the same clade with other classical PRV strains, indicating that this isolate might be a recombinant strain generated from the classical and variant strains. The results revealed the severe PRV epidemic in Yunnan Province and indicated that PRV variants are the major genotypes threatening the pig industry development.

Food media can affect the solubility of zinc oxide nanoparticles (ZnO NPs). Moreover, when a single digestive fluid and a three-step digestion system were applied to investigate the fate of ZnO NPs, several contradictory results were obtained. Here, we manipulated a novel semiclosed in vitro dynamic digestion system to investigate the difference in the released ionic zinc (Zn 2+ ) content in three types of artificial fluids in the presence of different food media. The results show that there was a significant difference in the released Zn 2+ content between the three different types of digestion systems in the presence of the same food media. In addition, the released Zn 2+ content was significantly different when different types of food media were applied to the same digestion system. These results demonstrate that the different levels of released Zn 2+ content can be ascribed to the difference in digestion systems and food media.

The proliferation of microorganisms is an important reason for meat spoilage and deterioration. Freezing and packaging by polymer films and preservatives are commonly used to preserve meat. While the energy consumption of freezing is very big, the polymer films made by petroleum bring up heavy environmental pressure. In the present study, biodegradable antibacterial ZnO@PLA (ZP) and ZnO@PVA/PLA (ZPP) nanocomposite films used as food packaging have been synthesized by the solvent evaporation method and coating method, respectively. Compared with films without ZnO NPs, ZP and ZPP both had long-term bacteriostasis for 24 and 120 h at temperatures of 25 and 4 °C, respectively. Moreover, the antibacterial effect showed positive relevance with the increase of the ZnO NP concentration. In addition, the antibacterial effect of ZPP was better than that of ZP in the same condition. Scanning electron microscopy showed that the numbers of methicillin-resistant staphylococcus aureus (MRSA) on ZP and ZPP were significantly reduced compared to that in the blank film, and ZPP caused the morphology of MRSA to change, which means that the antibacterial mechanism of ZP and ZPP composite films might be related to antibacterial adhesion. In conclusion, ZPP films have great potential to be regarded as the candidate of food packing to extend the shelf life of pork.