Journal of Food Safety最新文献

A loop-mediated isothermal amplification (LAMP) method combined with calcein was established for the detection of Staphylococcus aureus. LAMP primers were designed targeting the ASL18_04625 species-specific gene screened through bioinformatics and PCR analysis. The target gene and detection method demonstrated 100% specificity for S. aureus and no cross-reactions with other pathogens. For LAMP reactions, the results could be directly observed with the naked eye or evaluated by S-shaped amplification curves of fluorescence signals. The assay's detection limit was 3.395 × 10⁻⁴ ng/μL genomic DNA or 3.21 CFU/mL pure bacterial culture. Furthermore, the target bacteria of 8.5 × 10⁵–8.5 × 10⁰ CFU/mL could be accurately detected in spiked milk samples, and the overall detection process could be completed within 40 min. This method improved the accuracy and convenience for S. aureus detection and provied a dependable tool for the rapid screening of S. aureus.

In this study, polylactic acid (PLA) and polyadipic acid/butylene terephthalate (PBAT) blend polymer were used as matrix to prepare PLA/PBAT substrate film by twin-screw extruder. A series of multilayer films were prepared by starch-based adhesive by loading 1% chitosan (CS), 1% zinc oxide nanoparticles (ZnONPs) or 1% silver nanoparticles (AgNPs) with sodium alginate (SA) as three different coatings. Compared with PLA/PBAT, the combination of adhesive and SA-based antibacterial coating significantly improved the water vapor barrier, oxygen barrier and mechanical properties of the film, regardless of the type of antibacterial agent. The water vapor transmission of SA-based AgNPs coating film decreased from the original 5.77 × 10⁻¹⁴ to 3.41 × 10⁻¹⁴ g·cm·cm⁻²·Pa⁻¹·s⁻¹. The oxygen permeability of SA-based chitosan coating decreased from the original 74.35 × 10⁻¹⁴ to 6.40 × 10⁻¹⁴ cm³·cm·cm⁻²·Pa⁻¹·s⁻¹. The tensile strength of the SA-based AgNPs coating film increased from the original 264.79 to 286.22 MPa. The film is yellow and has good ultraviolet absorption capacity. Membranes doped with CS, ZnONPs or AgNPs inhibited the growth of Escherichia coli and Staphylococcus aureus. Among them, chitosan doped membrane has weak antibacterial activity, AgNPs doped membrane has the best antibacterial activity against E. coli and S. aureus, and has potential application prospects in active packaging.

In food preparation and manufacturing environments, surfaces contaminated with Salmonella can lead to outbreaks of Salmonellosis. We hypothesise that Salmonella resides on dry surfaces in a biofilm form leading to potential environmental persistence and transfer following contact. This is the first study reporting that Salmonella Typhimurium can form dry surface biofilm (DSB). Six disinfectants commonly used in the food industry were evaluated for their efficacy against the DSB. The two most efficacious formulations reduced bacterial viability in DSB by >99.99% when combined with mechanical removal (5 sec wiping; 300 g weight). Five out of six formulations significantly reduced bacterial transfer when combined with wiping. Complete eradication of Salmonella Typhimurium DSB was challenging, and mechanical removal was essential to produce a >99.99% reduction in bacterial viability within DSB. This study highlights a potential mode of survival of Salmonella Typhimurium on food-contact surfaces and DSB challenges for disinfection.

The present study aims to assess the antibacterial activity of endemic Moroccan Origanum essential oils (Origanum elongatum and Origanum compactum) alone and in association with antibiotics against multidrug resistant foodborne Salmonella. The well diffusion and microdilution procedures were used to evaluate the antibacterial activity. The synergistic interactions between antibiotics and EOs were determined using the checkerboard assay. The results of the antibacterial activity indicated that all of Salmonella serovars isolates that were examined were highly inhibited by EOs. This effect was confirmed by the microdilution technique, where 0.125% was noted as the smallest MIC value. Based on the obtained MBC values, O. elongatum shown a bactericidal action against the tested strains as indicated by the acquired MBC values. While O. compactum showed this effect against different serovars of Salmonella isolates. Origanum EOs could be employed as an alternative to the former protocols against resistant infectious diseases.

In this study, the effect of dielectric barrier discharge (DBD) cold plasma at different voltages (60, 70, and 80 kV) on the freshness and quality changes of rainbow trout was investigated. The results showed that the voltage of DBD was negatively and positively correlated with the total viable counts and degree of lipid oxidation, respectively. Based on the magnitudes of TVC and TVB-N, it was observed that the 70 kV DBD treatment extended the shelf life of fillets by at least 2 days. Furthermore, texture softening due to the extension of storage time was alleviated by the DBD treatment. Under 70 kV DBD treatment, the degree of myofibril fragmentation and the leaching of small molecule peptides were reduced. Microstructure analysis revealed that the DBD treatment delayed the textural deterioration during cryopreservation. Taken together, the shelf life of fillets could be extended by 70 kV DBD treatment, while its freshness and quality could be well maintained.

Staphylococcus aureus is an opportunistic zoonotic pathogen which secretes 24 different types of enterotoxins (SEs) and enterotoxin-like (SEls) proteins. Classical enterotoxins (SEA–SEE) are responsible for >95% of food poisoning outbreaks, of which SEA alone is responsible for >75% of them. This study was undertaken to develop a sandwich enzyme-linked immunosorbent assay (ELISA) for sensitive, specific, and quantitative detection of staphylococcal enterotoxins-A in food. Optimization of sandwich ELISA was attempted in two ways: rabbit polyclonal anti-SEA as a capture antibody and mouse monoclonal anti-SEA as a detector antibody, and vice versa. In the optimization of sandwich ELISA, mouse monoclonal anti-SEA as a capture antibody and rabbit polyclonal anti-SEA as a detector antibody yielded the highest sensitivity of 0.5–0.75 ng mL⁻¹. The developed assay was found to be highly specific and exhibited equivalent sensitivity to a commercial kit. The developed sandwich ELISA may be utilized for the detection of staphylococcal enterotoxin-A in food as a cheap alternative to available commercial kits. The developed sandwich ELISA may be useful for microbiological quality assurance of foods, especially in resource-limited developing countries.

Using stable chlorine dioxide (ClO₂) combined with slightly acidic electrolyzed water (SAEW), the quality variations of cold-stored large yellow croaker (Pseudosciaena crocea) were studied. The results of microbial indicators demonstrated that ClO₂ and SAEW treatment inhibited microbial growth. Moreover, ClO₂ + SAEW treatment had lower values of pH, malondialdehyde content, total volatile basic nitrogen, and higher water-holding capacity than those in other groups. From the results of free amino acids and trimethylamine, ClO₂ + SAEW treatment could delay the breakdown of umami amino acids and the accumulation of bitter amino acids in large yellow croaker. According to the results of microbial indexes and K-value, compared with sterile distilled water treatment, the shelf life of large yellow croaker with ClO₂ + SAEW treatment was extended for an additional 4 days. Therefore, ClO₂ + SAEW treatment is a potential method to preserve the flavor and quality of large yellow croaker during cold storage.

This study aimed to optimize minimal thermal treatment conditions for sour cherry juice using response surface methodology. The effects of ultrasound power (UP; 54, 35, 14 W), ultrasound time (UT; 8, 5, 3 min), ohmic electrical field strength (OE; 40, 30, 20 V/cm) and ohmic time (OT; 8, 5, 3 min) on total phenolic content (TPC), antioxidant activity (AA), color values (L*, a*, b*, $��∆�E�$), total monomeric anthocyanin content (TMAC), polymeric color (PC), color density (CD), polymeric color ratio (PC%), total mesophilic aerobic bacteria (TMAB) and yeast-mold count (YM) were investigated. UP significantly affected TPC, L*, a*, b*, and $��∆�E�$, while OE affected TPC, TMAC, PC, PC%, and TYC. UT affected TPC, L*, AA, CD, PC and PC%, and OT level affected TPC and b* values. The optimum points were determined by considering maximum TPC as 28.7564, maximum AA as 6.7714, maximum TMAC as 4.9616, maximum L* as 21.3839, maximum a* as 5.5396, maximum b* as 3.4260, maximum color density as 27.1412, minimum polymeric color as 17.3148, minimum PC% as 4.9253, minimum TYC as 1.9251 and minimum TMBC as 2.3301. The optimum levels were found to be 54 W, 8 min, 27.06 V/cm and 8 min. Improvements in TPC, TMAC and AA were determined after ultrasound-ohmic combination thermal treatment. Although ohmic (OH) has the effect of maintaining juice quality, its effectiveness is impacted by the electrochemical properties of food. By using ultrasound, the electrical conductivity values of juices were increased; thus, ultrasound improved the electrochemical properties of sour cherry juice. Further studies are needed to evaluate the effects of ultrasound-ohmic combination for juice processing on a large scale.

Moisture content detection has guiding significance for the storage and quality detection of rice. To detect moisture content rapidly and non-destructively, hyperspectral imaging technology (400-1000 nm) was employed to analyze rice with different moisture content, and Savitzky–Golay mixed standard normalized variable algorithm (SG-SNV) was used for spectral data pretreatment. Furthermore, a modified supervised locality preserving projections (MSLPP) method was proposed to extract spectral features. The modeling results showed that MSLPP had better spectral feature extraction performance. Finally, to improve prediction accuracy, the equilibrium slime mold algorithm (ESMA) was introduced to obtain the optimal parameters (c, g) of the support vector regression (SVR) model. And MSLPP–ESMA–SVR model had higher prediction accuracy and stronger robustness, with R²_p reaching 0.9755 and root mean square error of prediction reaching 0.8597%. Therefore, hyperspectral imaging technology combined with MSLPP–ESMA–SVR model is feasible to detect rice moisture content.

The current observational study aims to determine the extent to which main food safety principles are addressed in Slovenian cooking shows and whether the type of main actor or television channel significantly impacts adherence to good hygiene practices. In general, our results show that food handling presented to the audience in Slovenian TV cooking shows often deviates from the main food safety recommendations. A comparison between amateur and professional chefs has shown notable but statistically insignificant differences. While in the area of personal hygiene, more deviations were found among amateur than among professional chefs (p = 0.011), we can observe the opposite in the area of preparation practices, albeit with insignificant difference (p = 0.884). The current study provides further evidence that there is a large gap between what viewers see and what they should have seen in television cooking shows from a food safety perspective.