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Irradiation can extend the shelf-life of fish, but it may cause unacceptable change on quality. Since rose polyphenols have high antioxidant and antibacterial activities, this study evaluated the combined effect of polyphenol-chitosan coatings and irradiation (3 kGy) on the microbial and sensory qualities of carp fillets during storage at 4 °C. A dose of 3 kGy irradiation reduced the initial total viable counts (TVC) and psychrophiles, and increased the initial b and thiobarbituric acid reactive substance (TBARS) values. During storage, TBARS, TVC and psychrophiles of nonirradiated samples increased faster and were higher than those irradiated. Regardless of irradiation treatment, samples coated with chitosan containing rose polyphenols had lower TBARS, pH and bacteria than that in no coating or chitosan coating batches. Carp treated with combined treatment could preserve an acceptable sensory quality at the end of storage. The result indicated that polyphenol-chitosan coating combined with irradiation can maintain fish quality by preventing bacterial growth, oxidation, and changes in color and sensory acceptability.

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Skin excision, swabbing with cotton wool and whole carcass rinse are three common sampling methods of poultry carcasses.The objective of this study was to compare the three different sampling methods for enumeration and monitoring of bacteria on broiler carcasses. Total viable counts, Pseudomonas spp., lactic acid bacteria, Brochothrix thermosphacta and Enterobacteriaceae recovered by each sampling method were enumerated using the pour plate technique. Rinsing and excision recovered a similar level (P > 0.05) of the total viable counts, whereas swabbing yielded a lower level (P < 0.05). For Pseudomonas spp., lactic acid bacteria and B. thermosphacta, rinsing recovered the highest counts,followed by excision and finally the swabbing.There was no significant difference (P > 0.05) to detect Enterobacteriaceae by the three methods. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to monitor bacterial constituents. Compared with rinsing, the dice coefficient was 69.2% for excision and 32.3% for swabbing. The results revealed that great differences existed among the sensitivity of microorganism detection by the three methods, rinsing > excision > swabbing. Considering the bacterial recovery and DGGE profile, rinsing seems to be the preferable sampling method for enumeration and monitoring of bacteria on broiler carcasses whereas swabbing is poor. PRACTICAL APPLICATIONSThis work compared the efficiency of three sampling methods (excision, swabbing and rinsing) to evaluate bacteria on broilers using culture-dependent and cultureindependent methods. The results indicate that whole carcass rinse would be a preferable sampling method to monitor the bacteria on broiler carcasses, especially using the culture-independent method.

Bacillus subtilis shows high contamination and antibiotic resistance in the food industry due to their biofilm‐forming capacity. This study aimed to search a biopreservative to inhibit the biofilm formation of B. subtilis. The effect of garlic extracts, nisin, ε‐polylysine, and citric acid on bacterial growth, cell surface hydrophobicity, and cell morphology were observed to provide insight into the antibiofilm mechanisms. Results showed that nisin, ε‐polylysine, and citric acid completely inhibited the growth and biofilm formation of B. subtilis at 0.15, 0.09, and 1.5 mg/ml, respectively. Garlic extracts inhibited cell elongation, but cannot completely inhibit the biofilm formation even at 1.8 mg/ml. The antibiofilm activities of four biopreservatives were due to antibacterial activities, reduction in extracellular polymeric substances production, and cell surface hydrophobicity. Among these four biopreservatives, ε‐polylysine, which caused cell to collapse, had the highest antibacterial and antibiofilm activities followed by nisin, citric acid, and garlic extracts. Practical applications Bacillus subtilis shows high contamination and antibiotic resistance due to their biofilm‐forming capacity. Finding a biopreservative to inhibit the growth and biofilm formation of B. subtilis was important in food industry. This study could pave the way for controlling B. subtilis in planktonic and biofilm states.

Biological control by antagonistic microorganisms are an effective and environmentally friendly approach in postharvest disease management. In order to develop a biocontrol agent for fresh walnut fruit preservation, the potential biocontrol effects of Bacillus amyloliquefaciens RD.006 and Hanseniaspora uvarum FA.006 against the main fungal pathogen of walnuts were evaluated. Botryosphaeria species showed the highest detection, and the JNHT01 strain showed the strongest pathogenicity. Bot. dothidea JNHT01 caused gray mold and brown rot on fresh walnuts, and its incidence rate reached 100% after an 8 days incubation. The growth of this fungal strain can be promoted by lighting, with a maximum growth rate achieved at a pH of 7 and at 28 °C. B. amyloliquefaciens RD.006 and H. uvarum FA.006 supernatants at a concentration of 1–15% v/v showed antifungal activity. The mycelial growth inhibition rates of Bot. dothidea JNHT01 were 23.67–82.61% for B. amyloliquefaciens RD.006 and 1.45–21.74% for H. uvarum FA.006. During Bot. dothidea JNHT01 growth, the biomass, nucleic acid leakage, and malondialdehyde content gradually increased, while the DPPH scavenging capacity and SOD activity decreased. The B. amyloliquefaciens RD.006 and H. uvarum FA.006 strains showed antifungal activity by damaging fungal cell membranes and reducing fungal antioxidant activity. Moreover, the antifungal effect of B. amyloliquefaciens RD.006 was higher than that of H. uvarum FA.006. Hence, the RD.006 strain of B. amyloliquefaciens can be considered a potential biocontrol agent for the management of postharvest walnut diseases caused by Bot. dothidea.