Foodborne disease caused by Salmonella is an important public health concern worldwide. Animal-based food, especially poultry meat, is the main source of human salmonellosis. The objective of this study was to evaluate the prevalence and epidemiology of Salmonella contamination in raw poultry meat commercialized in China. Following the principle of systematic review, 98 sets of prevalence data were extracted from 74 publications conducted in 21 Chinese provincial regions. The random-effect model was constructed for subgrouping analysis by meat category, preservation type, and geographical location. The prevalence levels differed from high to low among raw poultry meat, including chicken, 26.4% (95% CI: 22.4–30.8%); pigeon, 22.6% (95% CI: 18.2–27.8%); duck, 10.1% (95% CI: 5.3–18.2%); and other poultry meat, 15.4% (95% CI: 12.0–19.5%). Prevalence data on the preservation type revealed that chilled poultry meat might be more likely to experience cross-contamination than non-chilled poultry meat in China. The distribution map of Salmonella for raw poultry meat showed that a higher prevalence level was found in the Shaanxi, Henan, Sichuan, and Beijing regions. All subgroups possessed high amounts of heterogeneity (I² > 75%). The scientific data regarding the differences in prevalence levels between meat category, preservation method, and geographical region sources might be useful to improve specific interventions to effectively control the incidence of Salmonella in poultry meat.

Antibiotic resistance in Salmonella is a global public health problem. Salmonella enterica serovar 1,4,[5],12:i:- (S. 1,4,[5],12:i:-), a monophasic variant of Salmonella Typhmurium, is one of the leading Salmonella serovars in several countries. This study aimed to assess the prevalence of antibiotic resistance to this serovar in China through a systematic review and meta-analysis. Nineteen eligible studies during 2011–2021 were included. A total of 4514 isolates from humans, animals, foods, and the environment were reported, which mainly concerned isolates found in Guangdong, Guangxi, Jiangsu, and Shanghai. A random-effects model was used to estimate the pooled resistance rate of S. 1,4,[5],12:i:-. Rates were found to be very high (values ≥ 75%) for tetracycline, ampicillin, sulfisoxazole, and streptomycin; high (50–75%) for nalidixic acid, amoxicillin–clavulanic acid, and chloramphenicol; and moderate (25–50%) for trimethoprim–sulfamethoxazole, kanamycin, trimethoprim, and gentamicin. The rates of resistance to ciprofloxacin, cefotaxime, ceftriaxone, cefepime, ceftazidime, and colistin were low (values ≤ 25%), but of great concern in terms of their current clinical importance. Furthermore, a high multidrug resistance rate (86%, 95% CI: 78–92%) was present in S. 1,4,[5],12:i:-, with the ASSuT pattern largely dominating. Subgroup analysis results showed that the high heterogeneity of resistance rates was not entirely dependent on isolated sources. Taken together, the severity of antibiotic resistance in S. 1,4,[5],12:i:- urgently requires the rational use of antibiotics in future infection control and antibiotic stewardship programs.

Listeria monocytogenes (L. monocytogenes), a foodborne pathogen, can cause human listeriosis. Listeriosis is a potentially fatal gastrointestinal illness, which is closely related to the spread of food to humans. We review the literature published during 2010–2019 to better understand the prevalence of L. monocytogenes in food products, incidence of human listeriosis, and their characteristics in Chinese mainland. We found the main sequence types (STs) strains from foods are similar globally, and the prevalence of L. monocytogenes from raw meat was the highest among all food products. The most common STs in food products and clinical cases were ST9 (serogroup I.2) strains and ST87 (serogroup II.2) strains, respectively. The ST87 strains being the most common STs of clinical cases might be related to the existence of Listeria pathogenicity island 4 gene and Chinese eating habits for ready-to-eat foods, among which the prevalence of ST87 strain was the highest in ready-to-eat foods. Therefore, more research should be conducted to explore the reasons for the L. monocytogenes isolates differences in food and clinical sources.

This study was carried out to investigate the effects of mild heat, lactic acid, benzalkonium chloride and nisin treatments on the inactivation, sublethal injury, and subsequent growth of Listeria monocytogenes. Results showed that the Bigelow model successfully described the thermal inactivation kinetics, while the Log-linear model with tail consistently offered the most accurate fit to LA, BC, and nisin inactivation curves of cells. Differential plating indicated that percentage of sublethal injury for nisin treated cells was significantly higher than that for the other three treatments. Compared to non-treated cells, significant extension of lag time was observed for all treated cells. The longer exposures to heat treatment contributed to the extended lag time of the survivors. While for LA, BC and nisin treated cells, the longest lag time was not observed at the most severe treatment conditions. The correlation analysis of sublethal injury percentage on the duration of lag time revealed that only heat treatment showed the significant correlation. Overall, the lag time analysis could evaluate a wide range of bacterial injury. Lag time of treated cells was significantly influenced by stress treatments and temperatures of recovery, however, there were not any significant changes in the maximum specific growth rate between treated and non-treated cells under isothermal recovery conditions. The information generated from this study is valuable for utilizing intervention strategies in the elimination or growth inhibition of L. monocytogenes.

Staphylococcus aureus (S. aureus) is one of the foodborne pathogens. This study aimed to investigate the prevalence of S. aureus in ready-to-eat (RTE) fruits and vegetables in Shanghai, China. We evaluated antibiotic resistance patterns and genetic diversity of isolates through whole genome sequencing. Our findings demonstrated that out of 143 market samples, 47 (32.87%) tested positive for S. aureus, with the prevalence rates ranging from 10% to 57.14% among 12 types of RTE fruits and vegetables. Most isolates were resistant to trimethoprim-sulphamethoxazole, oxacillin, and ampicillin. We identified a total of 15 antibiotic resistance genes associated with resistance to 6 antibiotics, such as fosfomycin, fluoroquinolone, and β-lactam. Adhesion genes and enterotoxin genes, including icaA, icaB, icaC, set, seg, and sec, were also identified. Seven multi-locus sequence types (MLST) were detected, two of which were novel (ST7208 and ST7986). Notably, ST705-t529 (34.04%) and ST6-t701 (27.79%) represented the predominant types of S. aureus. Furthermore, three of the isolates were confirmed to be methicillin-resistant S. aureus by mecA genes. Taken together, our results highlight the high prevalence of S. aureus in RTE fruits and vegetables, posing a potential threat to food safety, particularly due to its high level of antibiotic resistance.

A novel Gram-stain-positive bacterium, designated djl-8T, was isolated from farmland soil in Nanjing, Jiangsu province, PR China. Cells of strain djl-8T were aerobic, non-motile, non-spore-forming and rod-shaped. The organism grew at 25–37 °C, pH 5.5–8.0 and 0.5–4.0 % NaCl (w/v). The DNA G+C content was 69.3 mol%. The diagnostic diamino acid in the cell-wall peptidoglycan was LL-2, 6-diaminopimelic acid. The major fatty acids (>5 %) were iso-C16 : 0, anteiso-C17 : 0, iso-C15 : 0, 10-Me C17 : 0 and C17 : 1ω8c. The respiratory quinone was MK-8 (H4) and the major polar lipids were phosphatidylglycerol, phosphatidylinositol, diphosphatidylglycerol and unknown phospholipids. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain djl-8T is a member of the genus Nocardioides and shared the highest similarity with Nocardioides ginkgobilobae SYP-A7303T (97.1 %), followed by Nocardioides soli mbc-2T (96.9 %), Nocardioide spyridinolyticus OS4T (96.6 %) and Nocardioides maradonensis RP-B30T (96.6 %). Strain djl-8T exhibited low DNA–DNA relatedness with Nocardioides ginkgobilobae SYP-A7303T (26.9±2.1 %). On the basis of the morphological, physiological, biochemical and chemotaxonomic characteristics presented in this study, strain djl-8T represents a novel species of the genus Nocardioides , for which the name Nocardioides agrisoli sp. nov. is proposed. The type strain is djl-8T (=KCTC 39844T=CCTCC AB 2017058T).