Journal of Food Safety最新文献

Foodborne pathogens are a persistent threat to food and consumer safety. To mitigate outbreaks and contamination incited by these pathogens, the development of novel preventative safety controls and biorational inactivation measures are paramount. The objectives of this research were to evaluate the efficacy of pyrrolidine-based amide derivatives of decanoic (DEPY), lauric (LAPY), myristic (MYPY) and palmitic (PAPY) fatty acids for in-vitro inhibition and inactivation of various Gram-positive bacterial strains including Listeria monocytogenes (typically associated with foodborne illness), Bacillus subtilis, and Streptococcus mutans and Streptococcus sobrinus (both normally present in the oral cavity and involved with dental caries). Compared to no treatment (control), significant differences (P < 0.05) in the growth of Listeria strains were seen in-vitro with increased inhibition at higher amide concentrations (10,000–20,000 ppm). Furthermore, in-vitro growth inhibition of B. subtilis, S. sobrinus, and S. mutans was also observed with an effectiveness of LAPY>MYPY>PAPY>DEPY. In co-inoculation assays, LAPY treatment significantly reduced Listeria growth from 1.55 to >5.0 Log CFU/mL when a concentration range of 5 to 250 ppm was applied. Moreover, Listeria populations on pathogen-inoculated produce were significantly (P < 0.05) reduced from 0.51 to >3.00 Log CFU/g with greater inactivation on carrots compared to alfalfa, soybean, and pistachio. These results demonstrated the potential value of these FA amides against Gram-positive pathogenic bacteria. Biorational applications of antibacterial FA amides on fresh produce as a postharvest intervention process offers a great potential for enhancement of food safety.

Malathion is one of the commonly used organophosphate pesticides known to attack the central nervous system, posing a risk to humans and other animals upon exposure. The surface enhanced Raman spectroscopy (SERS) has been identified as an indispensable tool for chemical and biomolecular sensing. In this work, the facile fabrication of activated carbon (AC)-based colloidal SERS active substrate dubbed AC@AgNPs was designed by trapping AgNPs on the surface of AC for detection of varying concentrations of malathion. Apart from the higher concentrations of malathion, the rest of the normal Raman spectra of malathion standard solutions exhibited weak Raman signals. The intensity of peaks for 0.47 mg L⁻¹ were nearly non-existent which is an indication that the malathion pesticide could only be detected up to 0.95 mg L⁻¹ when using silica wafer. On the contrary, all the SERS spectra of malathion in wheat extracts adsorbed on AC@AgNPs substrate exhibited strong Raman signals. Quantitative analysis of malathion was performed by regression models developed using PLSR built with the raw spectra (no pretreatment), SNV-PLSR, and SNV-CARS-PLSR. The model with the most remarkable performance was established by using SNV-PLSR with r = 0.9869 and RPD = 4.61. This research shows that the proposed method can rapidly detect malathion residues in wheat, suggesting that it could be adopted for production process monitoring of other related food products to guarantee their safety for human and animal consumption.

Polymerase chain reaction (PCR) is widely used in several research areas and routine laboratory analyses, including foodborne pathogens detection. We aimed to investigate the knowledge about PCR-based methods and foodborne pathogens among undergraduate and graduate Brazilian students and professionals. A cross-sectional survey was carried out using an online questionnaire as data collection method. The questionnaire was validated and distributed through email and social networks. Data from 1246 respondents was collected. The knowledge scores were verified by correspondence analysis and discussed, 75.8% of the participants answered that they knew a foodborne pathogen and 71.4% of the participants answered that they did not study molecular biology techniques during undergraduate course. The highest level of knowledge was found among professionals with Masters' and PhD degrees. In conclusion, participants are not knowledgeable about PCR-based methods and the level of academic training influences the knowledge of analytical foundations. Most participants did not study PCR and its application in detecting foodborne pathogens during undergraduate course. We suggested that undergraduate courses in Food Engineering and in Food Science and Technology include mandatory molecular biology classes in academic programs.

In this study, the characteristics of Listeria monocytogenes isolated from enoki mushroom (Flammulina velutipes) collected from May to July 2019 were analyzed. The isolates were analyzed for strain characteristics, hemolysis, antibiotic resistance, heat resistance, and virulence genes (inlA, inlB, actA, plcB, and hlyA) were analyzed, and whole genome sequencing (WGS) analysis was performed for the strain with the highest risk. Seven isolates were obtained from some enoki mushroom samples. All isolates were β-hemolytic and had virulence genes. Antibiotic resistance test showed multi-drug resistance in L. monocytogenes strain SMFM2019-FV15 and SMFM2019-FV16. L. monocytogenes SMFM2019-FV16 showed higher heat resistance than the other isolates. According to the results L. monocytogenes SMFM2019-FV16 was selected as the strain with the highest risk. WGS for L. monocytogenes SMFM2019-FV16 showed that it had 14 antibiotic resistance genes and 43 virulence genes, and 35 single nucleotide variants in the 43 virulence genes were observed. These results indicate that these genetic variations might be related to the high risk of L. monocytogenes SMFM2019-FV16.

Campylobacter spp. cannot grow in raw milk, but it is able to transform into a viable but non-culturable (VBNC) state enabling the survival in such harsh conditions. In this study, Campylobacter jejuni survival in raw milk was investigated taken into consideration colony-forming units (CFUs) and VBNC cells. CFU from two different strains of C. jejuni (DSM 4688 and BfR-CA-18043) were enumerated at three temperatures (5°C, 8°C, and 12°C). In parallel, a viability real-time PCR was conducted to quantify intact and putatively infectious units (IPIUs) (comprising CFU and VBNC bacteria). The data generated were used to model the viability of C. jejuni during raw milk storage. Here, a one-step fitting approach was performed using parameter estimates from an intermediate two-step fit as starting values to generate tertiary models. Different primary model equations (Trilinear and Weibull) were required to fit the CFU and the IPIU data. Strain-specific linear secondary models were generated to analyze the effect of storage temperature on the maximum specific inactivation rate of the CFU data. The time of the first decimal reduction parameter of the IPIU models could be modeled by a strain-independent linear secondary model. The developed tertiary models for CFU and IPIU differ significantly in their predictions, for example, for the time required for a one log₁₀ reduction. Taken into consideration that VBNC could revert to a culturable state during the raw milk storage, our results underline the importance of considering IPIU and not only CFU to avoid underestimation of the survival of C. jejuni in raw milk.

Cross-contamination in the poultry slaughtering process can lead to thespread of zoonotic bacteria like Salmonellaenterica. Surfaces of equiptment may facilitate contamination of carcasses due to bacterial adherence and transfer. In this study, attachment, proliferation, and detachment of Salmonella Enteritidis and Escherichia coli were comparatively investigated on uncoated and silica-coated stainless-steel surfaces. The conditions occurring in the slaughtering workflow were imitated on laboratory scale, for example, spilling of contaminated liquid onto equipment surfaces, pressing or sliding of carcasses against surfaces during the slaughtering procedure, and cleaning of contaminated stainless-steel surfaces with water or detergent. Growth on stainless-steel surfaces was measured for 8 h. The applied silica coating led to a partly higher repelling effect without impact on proliferation for the target organisms on stainless steel. Further development of the coating and daption to the exact circumstances as well as more extending testing under real conditions would be the next steps.

Food and water-borne enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is a zoonotic bacterium that causes gastroenteritis and other human diseases. It has also been linked to chronic foodborne diseases with high mortality rates worldwide, particularly in children. Hence, this study was carried out to designed a peptide base kit for quick detection of E. coli in food. A peptide-based rapid detection kit was designed using an immunoinformatic technique and some antigenic target genes (stx1A, stx2B, escC, fliC, and eae). The antigenic gene sequences retrieved were screened for antigenicity, transmembrane topology, B-cells and helper T-cells. Selected epitopes were joined with appropriate linkers to form a chimeric protein which consists of five B-cell epitopes, five interleukin-4 (IL-4) inducer epitopes and five interleukin-10 (IL-10) inducer epitopes. The improved and optimized chimeric protein sequence was cloned in-silico in a suitable expression host, E. coli-strain K12. The designed peptide refined and validated tertiary structure was molecularly docked with the tertiary structures of each antigenic target gene. The physicochemical properties of the chimeric protein showed that the construct has an amino acid length of 295 amino acids, a molecular weight of 29.876 kiloDalton (kDa), an aliphatic index of 75.05 and an instability index of 14.82 which confers stability. The construct was hydrophilic with a GRAVY value of −0.261 and had a considerable half-life of 4.4 h (mammalian reticulocytes, in vitro), >20 h (yeast, in vivo) and >10 h (E. coli, in vivo). Conclusively, the final construct has successfully met the design requirements for the development of a lateral flow kit, which has the potential to provide fast and efficient detection of E. coli O157:H7. However, it is the additional validation through the vitro and in vivo techniques needed to confirm that this designed peptide based test kit.

Salmonella enteric serovar Typhimurium is one of the causative agents for non-typhoidal salmonellosis which is highly associated with the consumption animal products such as eggs, pork, and poultry. Phytochemicals present in plant extracts were reported to improve food safety by inhibiting the growth of foodborne pathogens. Herein, the antimicrobial activities of Citrus limon and Bambusa polymorpha extracts were evaluated for their effectiveness in reducing the log counts of strains of S. Typhimurium inoculated in ground pork. The incorporation of undiluted extracts has resulted in 3.95 and 1.88 log reduction of S. Typhimurium, respectively with 2 h of exposure. Phytochemicals in the extracts that interfere with the activity of outer membrane (OmpA) and efflux pump regulatory proteins (MdfA, RamA) were also identified and interactions were anticipated using molecular docking and molecular dynamics simulation (MDS) studies. This study has revealed that the major phytochemicals present in the extracts were viz. phenol-2-ethyl, paracresol, 2, 3-dimethoxybenzoic acid, cyclobarbital, 3-methylsalicylhydrazide, and 3-methoxy-5-methylphenol. In order to evaluate the drug likeness and toxicity, phytochemicals were screened for their physiochemical and absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties. ADMET studies has revealed that the screened phytochemicals with high docking scores had potent anti-bacterial abilities and could be used in drug design studies to develop natural plant products to preferentially target the outer membrane and efflux pump regulatory proteins of S. Typhimurium, which are critically important for the survival of S. Typhimurium under stress condition.

The food industry has inappropriate techniques for process and quality control and requires techniques that can provide information on the physical and chemical properties of food quickly and affordably. Food applications mostly focus on the identification of contaminants, with a few significant analytes, such as sugars, alcohols, amino acids, flavors, and sweeteners, as exceptions. Biosensors can bring about an analytical revolution to address the problems facing the food and agriculture industries. Potential applications for biosensors include contaminant detection, product freshness monitoring, content verification, and raw material conversion monitoring. These studies are costly and time-consuming due to the extraction or pre-treatment of samples. This review gives an overview of biosensors with their classification and application in different food industries such as the fruits and vegetable industry, dairy, and meat industries. The application of biosensors in detection, quality assurance, and food safety is discussed in detail with their potential application.

Here, the bactericidal efficacy and mechanism of action of the combination of alkaline electrolyzed water (AlEW) and acidic electrolyzed water (AcEW) on Pseudomonas aeruginosa biofilm were investigated, in comparison with single AcEW or AlEW treatment. The mature P. aeruginosa biofilm was formed at 120 h of cultivation. The number of bacteria in the P. aeruginosa biofilm decreased by 7.87 and 2.51 Lg CFU/mL after single AcEW and single AlEW treatment for 8 min, while the sterilization rate reached 92.2% and 33.1%, respectively. The group of AcEW (7 min) co-action with AlEW (1 min) had a P. aeruginosa sterilization rate of 85%. The AlEW (3 min) co-action with AcEW (5 min) treatment showed the best bactericidal efficacy. With this treatment, the sterilization rate achieved 94.4%, and the extracellular protein, polysaccharide, and DNA were degraded with the ratios of 70.8%, 77.7%, and 70.5%, respectively. Thus, AlEW exhibited a major washing effect, which can destroy the biofilm structure of extracellular polymers to a certain extent, while AcEW displayed a significant bactericidal effect. These results suggest that the AlEW co-action with AcEW treatment may be a promising candidate suitable for bacterial biofilm sterilization.