Journal of Food Safety最新文献

This research explores the interaction between Shiga toxin-producing Escherichia coli (STEC) O157:H7 and bacteria species commonly found in beef processing environments, specifically Carnobacterium, Lactobacillus, Comamonas, Raoultella, and Pseudomonas. The study investigated how various environmental conditions impact the formation of biofilms and the ability of O157:H7 to transfer from multispecies biofilm onto beef surfaces. For this purpose, a mixture of lactic acid bacteria (LAB), spoilage bacteria (10⁶ CFU/mL), and E. coli O157 (10³ CFU/mL) were combined as follows: LAB (T1): Carnobacterium piscicola + Lactobacillus bulgaricus + O157:H7, an spoilage bacteria (T2): Comamonas koreensis + Raoultella terrigena + O157:H7, an spoilage bacteria (T3): Pseudomonas aeruginosa + C. koreensis strain + O157:H7 and only O157:H7 as control (T4). Multispecies biofilms were developed on thermoplastic polyurethane (TPU) and stainless steel (SS) coupons at 10 and 25°C for 6 days, washed and stored for 6, 30, and 60 days at wet (60%–90% RH) and dry (20%–50%, RH) conditions. To evaluate O157:H7 transfer, beef cubes (3 × 3 × 1 cm) were placed on the coupons, followed by a 50-g weight (7.35 kPa). The experiment was repeated three times in triplicate for each strain combination. Results demonstrate that biofilms formed at 10°C were generally weaker (less biomass) than those at 25°C. Regardless of temperature, more viable O157:H7 cells were transferred to beef from moist biofilms on TPU surfaces. At 25°C, T3 biofilm exhibited the lowest O157:H7 transfer to beef by 1.44 log₁₀ CFU/cm² (p < 0.01). At 10°C, none of the multispecies biofilm (T1–T3) affected the number of O157:H7 transfers to beef (p > 0.05). Notably, O157:H7 was not detected on food contact surfaces with 30 and 60-day-old dry biofilms (T1–T4). Through enrichment, E. coli O157:H7 was recovered from multispecies biofilms T1, T2, and T3. Findings from this study imply that multispecies biofilms contribute to the persistence of O157:H7 under dry conditions, regardless of temperature. These results underscore the intricate influence of multiple environmental factors—including surface type, biofilm age, humidity, temperature, and the presence of other bacterial species—on the risk of beef contamination facilitated by biofilms.

The study compared the bio-detoxification capabilities of Saccharomyces cerevisiae and Candida albicans cell walls for aflatoxin M₁ (AFM₁). The yeast cell walls were disrupted using thermal shock-ultrasound, resulting in 75 nm particles, as confirmed by dynamic light scattering. These disrupted cell walls were then immobilized on nano-zeolite and entrapped in ca-alginate. SEM, FTIR & XRD confirmed their physical absorption on the nano-zeolite and entrapment in ca-alginate. Samples were exposed to AFM₁ for 15 min and 24 h, either in combination or free, before or after immobilization. HPLC analysis revealed significant variations in AFM₁ reduction. The highest reduction of 89.49% was observed after 15 min with alginate treatment, while the immobilized-entrapped C. albicans cell wall showed the lowest reduction of 24.77% after 24 h. Both free Candida cell walls and immobilized-entrapped Saccharomyces cell walls showed impressive detoxification abilities. Additionally, immobilized-entrapped cell walls are reusable and a sustainable choice for industrial use.

Biopolymer-based films present numerous environmental advantages. The current study aims to investigate the impact of storage time on the antimicrobial, antioxidant, and functional properties of pectin-based films containing Thymus capitatus (TEO) and Cinnamomum verum (CEO) essential oils (EOs). Films were prepared using the solution casting method; their different properties were evaluated over 1 month at room temperature. Both types of films displayed strong antimicrobial activity against Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes), Escherichia coli (E. coli), and Salmonella typhimurium (S. typhimurium). Pectin-based film incorporated with CEO displayed greater antioxidant activity than film incorporated with TEO. The two EOS increased the films' elongation at break and tensile strength. However, their moisture content and thickness decreased. The antibacterial and antioxidant activities of the CEO- and TEO-based films decreased after 4 weeks of storage, while moisture content increased. However, the films' mechanical parameters remained stable during the entire storage period.

This study focuses on nursing and medical students, assessing their knowledge, attitudes, and practices (KAP) regarding food safety. This non-random cross-sectional study was conducted between October and December 2022, with 1100 students (721 nursing and 379 medical) completing self-administered questionnaires. 949 (86.3%) of the respondents were female and 151 (13.7%) were male (mean age 20.90 ± 1.74). Nursing students outperformed medical students in food safety KAP scores (19.45 ± 3.19 vs. 19.13 ± 3.36), (10.61 ± 1.52 vs. 10.27 ± 1.80), and (46.96 ± 6.48 vs. 42.87 ± 6.49), with significant differences in food safety attitudes and practices (p < 0.05), as well as knowledge regarding personal hygiene, food preparation, cooking, foodborne pathogens, and cross-contamination (p < 0.05). Multivariate stepwise linear regression analysis revealed predictors of food safety knowledge, including age, residence, academic year, personal food poisoning experience, and familiarity with food safety authority (p < 0.05). Similarly, institutional context, gender, income, residential status, academic year, personal cooking habit, father's education level, and mother's education level had a substantial impact on the attitudes of students. Predictors of safe food handling practices encompassed institutional context, age, gender, family monthly income, residential status, academic year, father's education level, personal food poisoning experience, and familiarity with food safety authority (p < 0.05). These findings highlighted the need for targeted educational interventions to improve food safety KAP among nursing and medical students considering their forthcoming responsibilities as carers.

The perishability of aquatic products is a challenge for the processing of aquatic products, so it is better to choose suitable preservatives to prevent the degradation of proteins and the fission of their gel properties. Thus, this study investigated the effects of ultrasound-assisted chlorogenic acid grafted chitosan (GUA) soaking of sea bass (Lateolabrax japonicus) fillets on protein oxidation and gelation properties. The results showed that GUA could reduce the formation of protein carbonyls and maintain Ca²⁺-ATPase activity. Intrinsic fluorescence intensity (IFI) and SDS-PAGE results demonstrated that GUA stabilized the tertiary structure of protein and inhibited protein degradation. Interestingly, ultrasound attenuated the protein aggregation induced by the use of chitosan-grafted-chlorogenic acid (CS-g-CA), which has good particle size during storage. Meanwhile, GUA treatment endowed the gel with a dense network microstructure, increased water holding capacity (WHC), reduced water mobility, and improved MP gel color as well as textural properties.

This study aimed to examine the potential link between Bacillus cereus biofilm formation, virulence, and pathogenicity. The biofilm formation abilities of nine B. cereus strains isolated from food and two reference strains (ATCC 10876 and ATCC 25621) were measured using a crystal violet assay. Among the tested strains, three strains (GIHE 617-5, GIHE 86-09, and GIHE 728-17) and both reference strains were capable of biofilm formation. A positive correlation was obtained for higher cell surface hydrophobicity and increased biofilm formation. In contrast, HPLC analysis for elevated autoinducer-2 (Al-2) production revealed a negative impact on biofilm formation. PCR data indicated that all tested strains were capable of producing common B. cereus enterotoxins, including Hbl—A, C, and D, CytK, Nhe—B and C, EntFM, and BceT, but were negative for production of the emetic toxin cereulide and the pore-forming toxin Hly II. Meanwhile, RT-PCR data revealed a close correlation between high biofilm formation and the upregulation of several tested virulence genes for selected strains. However, elevated upregulation of virulence genes was not consistent in all of the higher biofilm-forming strains. Cytotoxicity analysis revealed higher virulence characteristics compared to those of low biofilm-forming strains.

The assurance of food safety is paramount, especially concerning ready-to-drink products like milk tea. This research sought to gauge the safety perceptions of both student and office worker demographics towards this beverage using a combination of direct and online surveys. The data reveals that 84.6% of respondents express significant concerns about hygiene and safety standards within milk tea consumption. A substantial portion of these consumers indicates a willingness to expend between 2-4 USD per serving. Alarmingly, analyses of several popular milk tea brands have identified considerable concentrations of pathogenic microorganisms: Coliform counts were observed at 10⁸, E. Coli at 10¹⁰, Pseudomonas at 10⁸, and Salmonella at 10⁴ (CFU/mL). A primary suspected avenue of this microbiological contamination appears to be ice, which exhibits levels exceeding nationally stipulated safety thresholds.

Low-energy X-rays can be used to reduce the number of pathogenic microorganisms in fresh produce, but the efficacy of this process against internalized bacteria in leafy greens has not yet been reported. The leaves of iceberg lettuce were cut into pieces and subjected to vacuum perfusion to force the foodborne pathogen cells into the intercellular spaces within the leaves. Sodium hypochlorite (200–400 ppm) washes were not effective in inactivating internalized bacterial cells from lettuce leaves. In contrast, treatment with 1.5 kGy low-energy X-rays reduced Escherichia coli O157: H7, Salmonella enterica Serovar Typhimurium, and Listeria monocytogenes levels by 6.89, 4.48, and 3.22 log CFU/g, respectively. Additionally, the maximum dose of X-rays did not adversely affect the color or texture of lettuce. These results suggest that low-energy X-ray treatment can be used to control internalized and surface-adhering pathogens in leafy vegetables without affecting product quality.

Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST) are the most commonly reported serotypes detected for the occurrence of Salmonellosis through foodborne transmission in recent years. In this study, a phagomagnetic separation in combination with qPCR (PhMS-qPCR) based on phage T102 as a recognition element was developed for rapid enrichment and detection of Salmonella in dairy products. Phage T102 was coated onto magnetic beads for capturing Salmonella from samples through magnetic separation, with a capture efficiency of ~90% demonstrated. During the subsequent qPCR process, captured Salmonella was identified by detecting the OmpC gene, and specific sdf and STM4495 genes to further distinguish the serotypes of Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST), respectively. The whole procedure can be performed in 2.5 h with a low detection limit of 10 CFU/mL in PBS. Subsequently, this detection strategy was successfully applied for the detection of Salmonella and serotype identification in spiked milk samples. This cell separation and detection system offers a promising alternative for rapid and accurate detection of Salmonella or Salmonella spp.

Microbial contamination in cooked rice-based foods poses a global concern due to rice's widespread consumption. This review aims to consolidate information on harmful microorganisms associated with such foods from various countries and their adverse effects on consumers. Additionally, it explores the reported causes of microbial contamination in cooked rice-based dishes and proposes an intervention strategy for safer consumption. The findings highlight that ready-to-eat cooked rice-based foods may harbor unsafe levels of microorganisms like Bacillus cereus, Staphylococcus aureus, and Aspergillus spp. A recommended solution is the application of microwave pasteurization. This method involves cooking rice in pasteurized packaging, minimizing human contact, and effectively controlling harmful microorganisms. Microwave pasteurization emerges as a promising approach to ensure the safe consumption of cooked rice-based foods by reducing microbial contamination levels.