Journal of Food Safety最新文献

Intense pulsed light (IPL) is an efficient sterilization technology for instantaneous intense UV predominantly, while the decontamination was weakened on green Sichuan pepper (GSP) for “shadow effect.” Catalytic infrared (CIR) has excellent decontamination on uneven surfaces for long-wave diffraction while was prone to cause flavor decline for “thermal effect.” In this study, a combined method of CIR and IPL was attempted to settle the dispute of decontamination effect and flavor decline on GSP. The inactivation kinetics on the change of bacterial enumeration over sterilization time were determined, and the results showed the sterilization effect of IPL on GSP could be improved significantly after CIR pretreatment, which was promoted from 0.65 ± 0.07 to 2.62 ± 0.07 Lg (p < 0.05), and could realize the active bacteria on commercial GSP was below 100 CFU g⁻¹. Moreover, the flavor of GSP was measured on color and aroma changes, volatile oil content, and total alkaloid content, and the antioxidant function was measured on total reducing power, ABTS^+•, and ^•OH⁻ clearance rates. The results showed CIR could give rise to color change and volatile oil decrease of GSP, which indicated that the treatment time of CIR should be restricted in 5 min based on relevant Chinese national standard. CIR and IPL showed a difference to several oxygen free radicals, and the impact could be weakened by a combined method. In conclusion, under the same sterilization rate, CIR pretreatment could promote the decontamination of IPL on GSP and could weaken the influence of CIR or IPL on the quality of GSP.

The fresh-cut fruits and vegetables industry has developed rapidly in recent years, with pineapple being a popular fruit. The quality of pineapple plays a crucial role in determining its market value. This research explored the potential of diffuse reflectance hyperspectral imaging (HSI) and fluorescence hyperspectral imaging (FHSI) in monitoring L*a*b*, pH, and soluble solids content (SSC) of fresh-cut pineapples during cold storage. Fresh-cut pineapples were stored at a temperature of 4°C for 0–5 days, with daily acquisition of diffuse reflectance and fluorescence hyperspectral images at 380–1000 nm, along with measurement of quality indices. Changes in spectral properties and quality indices during cold storage were analyzed. Seven preprocessing algorithms were used to preprocess two types of spectra. Subsequently, five feature selection methods were employed to extract feature variables from the preprocessed spectra. The Partial Least Squares Regression (PLSR) models were constructed to predict the various quality indices. Data fusion methods were introduced to leverage the complementary information from different spectra. Both feature-level and decision-level fusion methods demonstrated improvement in model accuracy. The hybrid fusion method, combining the advantages of these two fusion methods, effectively enhanced the prediction accuracy of all quality indices. The determination coefficients (R²) for predicting L*a*b* consistently exceeded 0.8, while the R² for predicting pH was close to 0.8, and the R² for predicting SSC reached 0.91. In summary, the quality indices of fresh-cut pineapples can be accurately predicted using diffuse reflectance HSI and FHSI, with model accuracy further enhanced through multi-level data fusion methods.

Sodium diacetate is recognized for its high efficiency as a preservative, demonstrating strong antibacterial properties that help extend the shelf life of food products. However, it is still unclear how it influences spores. This research investigated the influence of sodium diacetate on the germination and outgrowth stage in the revival process of Clostridium perfringens (C. perfringens) spores. The germination and outgrowth rate of spores after sodium diacetate treatment were measured. The changes of spore inner membrane were monitored by laser confocal microscope, electron scanning microscope and macromolecular leakage. The interaction between sodium diacetate and DNA was investigated by EB fluorescence probe, and the finding was verified by the outgrowth of spores in ham sausage. An investigation into the effects of sodium diacetate treatment on the biological activity, inner membrane permeability, morphology, and DNA integrity of spores devoid of both the coat and cortex revealed that sodium diacetate significantly hindered the transition of germinated spores into vegetative cells. In the presence of sodium diacetate, C. perfringens spores underwent germination, characterized by the hydrolysis of the spore cortex and the disassembly of the spore coat. As the spores advanced into the outgrowth phase, sodium diacetate penetrated their structure, causing damage to the inner membrane and compromising DNA integrity. Moreover, sodium diacetate was demonstrated to effectively inhibit spore outgrowth in ham sausage. This study provided theoretical guidance and references for the application of sodium diacetate in food to control the germination and outgrowth of spore-forming bacteria.

This study aimed to determine the chemical profile, cell-based safety, antioxidant properties, antibacterial effect, and mode of action of Lactobacillus helveticus postbiotics (LHPs) against Escherichia coli O157:H7 and multidrug-resistant Staphylococcus aureus. LHPs exhibited significant radical scavenging activity (83.59% ± 4.21% for Hydroxyl RSA; 98.33% ± 2.47% for DPPH; and 21.67% ± 2.79% for linoleic acid peroxidation inhibitory), and antibacterial action toward MDR S. aureus (inhibition zone (IZ): 32.76 mm; minimum inhibitory concentration (MIC): 36.00 μg/mL; minimum bactericidal concentration (MBC): 45.00 μg/mL; minimal effective concentration (MEC): 25 mg/mL for whole milk, and 30 mg/mL for ground meat) and E. coli O157:H7 (IZ: 25.63 mm; MIC: 60.00 μg/mL; MBC: 90.00 μg/mL: MEC: 35 mg/mL for whole milk, and 45 mg/mL for ground meat) (p < 0.05). As an antimicrobial mode of action, significant alterations in the bacterial surface charge, membrane integrity, biofilm generation, auto-aggregation ability, and swimming/sliding motility, along with the subsequent intracellular content leakage from MDR S. aureus and E. coli O157:H7, were detected after treatment with LHPs (p < 0.05). LHPs exerted a promoting influence on MV-4-11 macrophage cell viability, leading to a considerable increase in the functions of SOD and GSH-Px in these cells. As well, LHPs caused a reduction in the production of NO and a drop in ROS levels (p < 0.05). Therefore, LHPs are a promising approach against MDR S. aureus and E. coli O157:H7 proliferations and have the capacity to be used in the food sector to combat safety issues caused by pathogenic microbes.

Salmonella spp. and Staphylococcus aureus have been linked to foodborne illnesses caused by the consumption of processed meat products. This study examined the growth probabilities of these two pathogens as affected by sodium chloride (salt), sodium lactate, and sodium diacetate in a solid medium for using these three additives to improve the microbial safety of processed meat. Sterilized tryptic soy agar (TSA, 200 μL) formulated with a combination of salt (3%–8%, a_w 0.98–0.93), lactate (0%–2.4%), and diacetate (0%–0.25%) and inoculated with Salmonella spp. or S. aureus was dispersed into 96-well microplates and incubated at 37°C for 7 days. After incubation, a well showing any Salmonella spp. or S. aureus colonies was denoted as a growth event, otherwise a no-growth event. The number of growth events for each formulation was recorded. The effects of the additives on the growth event were analyzed by logistic regression to identify the growth and no-growth boundaries and the formulations that may prevent the growth of Salmonella spp. or S. aureus. For Salmonella spp., the observed minimum no-growth concentrations in TSA were 3% salt with 0.8% lactate+0.2% diacetate or 1.6% lactate+0.1% diacetate, 4% salt with 2.4% lactate, 5% salt with 0.25% diacetate, 6% salt with 0.8% lactate+0.15% diacetate, 7% salt with 0.8% lactate or 0.15% diacetate, and 8% salt alone. For S. aureus, the concentrations were 3% salt with 2.4% lactate+0.2 diacetate, 5% salt with 1.6% lactate+0.2% diacetate, 7% salt with 0.8% lactate+0.25% diacetate, and 8% salt with 0.8% lactate+0.20% diacetate or 1.6% lactate+0.15% diacetate. These no-growth formulations also inhibited the growth of both pathogens in cooked meat samples. Mathematical models were developed to describe the effects of the additives on the growth probabilities of Salmonella spp. and S. aureus. Findings from this study may be used for formulating refrigerated and shelf-stable meat products to reduce Salmonella spp. and S. aureus risk.

Fresh produce safety is important for consumer health. Intervention technologies that can lessen the pathogen threat and produce contamination is needed. In this research, cold plasma (CP), pulsed light (PL) and their combinations were assessed for inactivating Escherichia coli O157:H7 on Romaine lettuce. The effects of treatment on native microflora and sensory attributes of lettuce was also determined. An inoculum of multiple E. coli O157:H7 strains was employed for this study. Lettuce leaves were spot inoculated and then treated with PL (1–60 s), CP (15–60 s) or their optimized treatment combinations. A 30 s treatment with PL (fluence dose of 31.5 J/cm²), was optimum which provided 2.7 log CFU/g reduction of the pathogen, while 45 s treatment of CP was optimum, that delivered 2.1 log CFU/g log reduction. Combinations of PL and CP treatments were investigated for enhanced inactivation. For PL-CP combination, inoculated lettuce was treated with PL for 30 s followed by 45 s of CP exposure. While for CP-PL combination, treatments sequences were 45 s of CP treatment followed by 30 s PL treatment. Both combination treatments, PL-CP and CP-PL, resulted in synergistic inactivation of E. coli cells with > 5 log reductions of the pathogen. These combination treatments significantly (p < 0.05) reduced native microbiota and slowed their growth during storage. Additionally, treatment effects on lettuce quality was not adversely impacted. PL and CP are both non-aqueous, sustainable technologies. This study demonstrated that integration of PL and CP technology can enhance microbial safety and preserve quality of Romaine lettuce.

This study aimed to elucidate the antibacterial mechanism and antibiofilm activity of ginger essential oil (GEO) against Shewanella putrefaciens. On the basis of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), alkaline phosphatase (AKPase), succinate dehydrogenase (SDH), and glucose-6-phosphate dehydrogenase (G6PDH) activities were analyzed to evaluate the damage degree of S. putrefaciens on cell wall and membrane, and the microstructure was observed by scanning electron microscope (SEM) to evaluate the action effect against S. putrefaciens. The results showed that the MIC and MBC of GEO against S. putrefaciens were 27.8125 mg/mL and 55.625 mg/mL, respectively. The surface structures and cell membrane of S. putrefaciens were rigorously damaged by 1 MIC and 2 MIC GEO, leading to the leakage of cellular nucleic acids, protein, and β-galactosidases from the bacterial cells. GEO could not only decrease the biomass of biofilm but also remove mature biofilm. In addition, GEO could reduce the production of exopolysaccharides and extracellular proteins, and could lessen the metabolic activity of biofilm cells. These results demonstrated that GEO exhibited efficient antibacterial characteristics against S. putrefaciens, which could act as a natural antibacterial and antibiofilm agent on the preservation of aquatic products.

Information on the microplastic (MPs) migration, particularly phthalate acid esters (PAEs) in packaged seafood, is limited to a few studies. The aim of this study is to follow the possible migration potential and speed of phthalates in rainbow trout (Oncorhynchus mykiss) fillets stored in vacuum packaging depending on the storage temperature, as well as to determine the polyethylene polymer detection. For this purpose, the fillets were randomly distributed as three pieces in each bag, vacuum-packed, and stored at commonly used temperatures (+4°C and −20°C) for 3 months. On the first day of storage in fillet and packaging materials, in certain periods of storage, the phthalate content in the fillet of each temperature group was determined. It has been determined that the chemical composition of the bag used in the vacuum packaging process is affected by the temperature depending on the storage period, and different polymer types are formed in the packaged material. Ten types of PAEs including diisobutyl phthalate (DIBP), dibutylphthalate (DBP), di-n-pentyl phthalate (DPENP), di-n-hexyl phthalate (DHEXP), butylbenzylphthalate (BBP), di-(2-ethylhexyl)-phthalate (DEHP), dicyclohexyl phthalate (DCHP), di-n-octylphthalate (DNOP), di-iso-nonylphthalate (DINP), and di-isodecylphthalate (DIDP) were recorded in the packaging material and stored fillets. It was determined that the dominant PAE in the fillets were DPENP, and DEHP in the package at all temperature applications and storage periods. The findings help monitor the presence and migration of PAEs in foods and provide a motivating model for adopting the right technologies.