Bacillus cereus in low-temperature chicken sausage and its processing environment samples was counted following the GB 4789.14-2014 National standards for food safety-microbiological examination of food-test for Bacillus cereus. Polymerase chain reaction (PCR) and biochemical tests were combined to identify eight isolates and determine their virulence genes. The drug susceptibility of the isolates was determined using the disc diffusion method. The results showed that the detection rate of B. cereus in five samples of spoiled low-temperature chicken sausage was 100%. Based on the results of biochemical tests, 16S rDNA sequencing, the house-keeping gene gyrB and the Bacillus thuringiensis specific gene cry, all isolates were identified as B. cereus. Each strain carried at least five virulence genes, among which, the detection rate of the non-hemolytic enterotoxin gene was the highest. Five strains of B. cereus carried the nheA, nheB, and nheC genes simultaneously, but did not carry the vomitoxin gene ces. Strain A3 carried all virulence genes except ces, and was the strain that carried the largest number of virulence genes. Among the 22 antibiotics detected, the 8 strains of B. cereus were resistant to 8 antibiotics, including ampicillin, ceftazidime, cefazolin, streptomycin, penicillin, kanamycin, cotrimoxazole and cefuroxime sodium. In conclusion, the level of contamination of B. cereus in low-temperature chicken sausages was high, and the obtained isolates carried a wide range of virulence genes and were highly resistant to drugs, posing a risk of foodborne diseases and a threat to food safety.

This study systematically investigated the impact of covalent binding of tannic acid (TA) to different proteins on protein structure and the stability of a nanoemulsion of Perilla essential oil (PEO). Additionally, the antimicrobial activity of the nanoemulsion was assessed. The interactions between TA and various proteins were explored using fluorescence spectroscopy and Fourier transform infrared (FTIR) spectroscopy, revealing that TA exhibited the most binding sites (n = 1.65) to whey protein isolate (WPI), forming a stable protein-TA complex. The emulsion prepared using TA had high stability. One-factor-at-a-time experiments showed that the emulsion prepared under the conditions of 675 W ultrasonic power and an oil-to-water ratio of 1:9 had the smallest droplet size of (292.3 ± 1.96) nm, a relatively high absolute zeta potential value of (–62.5 ± 0.29) mV, and the highest PEO encapsulation efficiency of (74.51 ± 0.35)%. The interaction between WPITA complex and PEO could stabilize the structure of the emulsion, and the emulsion maintained high stability at 4 ℃ for 28 days. Furthermore, emulsion encapsulation significantly reduced the loss of PEO, with the loss of PEO in the emulsion being only one-third of that of the pure essential oil under the same conditions. This study provides new ideas for future research on the synthesis of protein-polyphenol complexes and the encapsulation of volatile substances, laying a foundation for expanding the application of nanoemulsion in the food industry.

This study used traditional culture and high-throughput sequencing techniques to analyze the status of microbial contamination on the surface of chicken carcasses and that of pre-cooled water during the slaughter process of yellowfeathered broilers, including plucking, evisceration, pre-cooling, and packaging. The results demonstrated that the total bacterial count of chicken carcasses after plucking, evisceration, and pre-cooling were 4.82, 5.03, and 4.68 (lg (CFU/g)), respectively, indicating that the slaughtering process did not achieve good decontamination; instead, there was severe microbial contamination in the carcasses after slaughter. High-throughput sequencing analysis showed that at the genus level, the dominant spoilage bacteria on the surface of broiler carcasses and in pre-cooled water during slaughter and processing were Moraxella, Pseudomonas, Staphylococcus, Lactobacillus, Macrococcus, Psychrobater, and Acinetobacter. Principal component analysis (PCA) showed no significant difference among primary and secondary pre-cooled water, pre-cooled chicken carcasses, and packaged chicken carcasses in terms of bacterial community composition at the genus level, but a significant difference between them and plucked carcasses and eviscerated carcasses. This indicates that the composition of bacteria contaminating pre-cooled water determines that on the slaughtered carcasses. Considering the changes in the composition and abundance of bacteria contaminating yellow-feathered broiler carcasses during the slaughter process, control approaches are needed to ensure the quality and safety of yellow-feathered broiler products.