Yang Jiao

Human norovirus (HuNoV) is one of the most important foodborne viruses and poses a significant risk in frozen foods along the cold chain. Traditional disinfectants exhibit reduced efficacy in frozen matrices and often fail to meet the requirements for food applications. This study optimized and evaluated a novel antifreeze–peracetic acid formulation (Af-PAA) for application on frozen foods, achieving disinfection performance at −40 °C. The formulation was optimized using four indicator microorganisms, with effective Af-PAA concentrations of 200 mg/L for Escherichia coli, 200 mg/L for Staphylococcus aureus, 500 mg/L for Candida albicans, and 2000 mg/L for Aspergillus niger. HuNoV GII.4[P31] propagated in zebrafish was inoculated onto frozen food samples. The frozen blueberries (500 mg/L), carrots (500 mg/L), chicken breast (2000 mg/L), and Arctic shrimp (2000 mg/L) were then subjected to Af-PAA treatment at −40 °C for 60 min with 60 s vortex mixing. RNase-RT-qPCR analysis showed a 3.0–3.1 log₁₀ reduction in RNase-resistant HuNoV RNA signals across all tested food under the corresponding treatment concentrations. No visual changes were observed in treated foods. This study demonstrated that Af-PAA met tested food disinfectant requirements and effectively inactivated indicator microorganisms. HuNoV signals were also markedly reduced on the tested foods. These findings support its application for microbial risk control in cold-chain foods.

Norovirus represents one of the primary pathogens responsible for gastroenteritis on a global scale, exerting a significant impact on foodborne illnesses. In recent years, China has emerged as a region of particular significance with regard to the occurrence of norovirus outbreaks. This study presents a systematic review of norovirus outbreaks in China, offering a comprehensive overview and analysis of norovirus epidemics. A total of 680 articles reporting 798 outbreaks were included from four databases (CNKI, CHINA Wanfang, Web of Science, and PubMed). Firstly, an overall historical review of norovirus outbreaks in China over the past two decades is conducted, detailing the fluctuations in reported outbreak numbers and cases influenced by different global strains and the COVID-19 pandemic. A comparison of the changes in the scale of outbreaks (the number of cases, attack rate, duration, and reporting time), significant differences are found in the number of cases and duration of outbreaks (P<0.001). Furthermore, the epidemiological characteristics are examined from five perspectives: region, seasonality, setting, transmission, and genogroup. It was found that high-incidence regions are concentrated in the southern and eastern regions of China, with outbreaks primarily occurring in winter. Schools are identified as key outbreak setting, and foodborne transmission is the main mode of transmission. The GII genogroup is particularly prevalent, with GII.2 and GII.4 being the most dominant. Based on above findings, the article also cross-analyzes seasonal variations in different provinces and transmission modes under different settings and genogroups. In most settings, foodborne transmission is the primary mode, whereas person-to-person and waterborne transmission prevail in settings like schools and communities, respectively. The GII genogroup primarily spread through person-to-person contact, food, and aerosols caused by vomiting. In contrast, the GI genogroup and I/II mixed genogroups mainly spread through water and food.