Journal of Food Safety最新文献

The nanoliposomes containing ferrous sulfate were produced by thin-layer hydration, sonication, and coated with nano-chitosan. Chitosan coating (0.2% w/v) and various lecithin: ferrous sulfate ratios (5:1, 10:1, and 20:1 w/w) were characterized based on the antimicrobial properties. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ferrous sulfate against Escherichia coli ATCC 2592 and Staphylococcus aureus ATCC 25923 were 1000 and 1500 mg/mL, respectively. The incorporation of ferrous sulfate into the nanoliposomes lowered its MIC and MBC values. The optical density (OD₆₀₀) of E. coli (0.516) and S. aureus (0.738) in the control culture exposed to free ferrous sulfate and ferrous sulfate loaded nanoliposomes with different levels of lecithin to ferrous sulfate (5:1, 10:1, and 20:1 w/w) at MIC values decreased around 12.04% and 22.19%, 16.55% and 35.56%, 25.57% and 35.56%, 51.78% and 63.59%, respectively. Exposure of E. coli and S. aureus to free ferrous sulfate and ferrous sulfate loaded nanoliposomes decreased AUC and increased the lag phase of both bacteria (p < 0.05). A significant reduction was observed in the optical density and AUC of the E. coli and S. aureus cultures exposed to chitosan-coated nanoliposomes containing ferrous sulfate. The highest percentage reduction in final optical density and the lowest AUC of E. coli and S. aureus cultures were observed after being exposed to chitosan-coated nanoliposomes prepared at lecithin: ferrous sulfate ratio of 20:1 (w/w).

As the market of natural fruits and vegetable (F&V) beverages constantly grows, there is a rising interest in alternative preservation methods, like non-thermal technologies and natural preservatives, to inactivate detrimental factors while providing fresh-like quality characteristics. This study aimed to evaluate and select a treatment combining gamma irradiation (GI: 0, 0.5, 1 kGy), nisin (0, 50,100 UI/mL) and green tea extract (GTE: 0, 0.2%) in order to improve and preserve the microbiological and nutritional quality of a mixed F&V smoothie, extending its shelf-life and ensuring its safety. A radioresistance study positioned Listeria innocua as the design microorganism. The combination of 1 kGy of GI with 50 or 100 IU/mL of nisin effectively reduced Listeria counts by over 5 log, maintaining their counts below the detection limit during 28 days of refrigerated storage. Irradiated samples showed significant reductions (p < 0.05) in deterioration enzymes, without altering the smoothie's physicochemical characteristics and color. Moreover, the combination of 1 kGy of GI and 100 UI/mL of nisin extended the microbiological shelf-life by 21 days. Although irradiation reduced betacyanin content, combining it with GTE (0.2%) achieved excellent stability for these compounds. GI caused increases (10%) in the content of total polyphenols (TPC), although the antioxidant capacity was similar to the control. Moreover, samples added with GTE exhibited TPC, DPPH, and FRAP values of 6.5, 11.5, and 8.5 higher than control, respectively. Therefore, the GI, nisin, and GTE combination produces a safe smoothie with outstanding microbiological, physical, chemical, and nutritional attributes.

The influence of frequency, electric field strength, and nonthermal effects during ohmic heating (OH) on the inactivation of Escherichia coli O157:H7 in pomelo juice was investigated. Pomelo juice was inoculated with a specific density of E. coli O157:H7 and then treated with OH at frequencies ranging from 50 Hz to 20 kHz and electric field strengths of 20, 30, and 40 V/cm. The results showed that 60 and 500 Hz were more effective in inactivating E. coli than other frequencies. As electric field strength increased, inactivation also increased. Transmission electron microscopy analysis revealed that the cell membrane of E. coli O157:H7 treated with OH underwent more pronounced changes than cells treated with conventional heating (CH). OH could inactivate E. coli O157:H7 at lower temperatures and in a shorter time than CH. The nonthermal effect of OH increased the inactivation of the pathogen in pomelo juice. These findings demonstrated the potential of OH for pasteurizing pomelo juice.

Fruit preservation plays a vital role in the food industry by addressing economic and environmental issues. The low toxicity and mechanical flexibility of sodium alginate have made it an excellent choice for the preparation of new-generation edible coatings in recent years. This quest for sustainable solutions has opened the field of biopolymers, with one such option being sodium alginate as a polymer. Current research trends explore the techno-functional properties of sodium alginate and have been extended to include film formability, gas permeation, and mechanical attributes as necessary determinants that govern coating performance. The synergy between the techno-functional and bioactive landscapes enables sodium alginate to play a multifaceted role in tailor-made coatings that are associated with diverse fruits while catering to on-shelf stability, final product elegance, and appealing to evolving trends of sustainably sourced health-conscious food choices. This review explores the novel potential of sodium alginate-based formulations in controlled bioactive release, enhanced antioxidant properties, and its role in nutrient retention. The integration of sodium alginate with natural antimicrobials for food safety presents an innovative approach to reducing postharvest losses while maintaining fruit quality. It also provides insights into the properties and applications of sodium alginate-based edible coatings.

Escherichia coli (E. coli) O157: H7 is a critical pathogen due to its association with severe conditions like hemorrhagic colitis and hemolytic uremic syndrome. The prevalence of this pathogen underscores the urgent need for effective food and environmental safety measures. Among emerging innovations, aptamer-based biosensors (aptasensors) offer increased sensitivity and reduced detection times compared to traditional methods for identifying E. coli O157: H7. Aptamers, short single-stranded DNA (ssDNA) or RNA molecules, act as bio-recognition elements, exhibiting high specificity and affinity for foodborne pathogens. This scoping review examines recent advancements in aptasensor technology over the past 5 years, focusing on platforms targeting E. coli O157: H7 detection. Key elements such as detection targets, sample types, transducers, sensing mechanisms, fabrication methods, and detection limits were analyzed to identify the strengths and limitations of current aptasensor platforms. The findings indicate that most optical aptasensors, particularly fluorescence-based ones, have been developed for detecting E. coli O157: H7 in water, food, and milk samples. Currently developing aptasensors show promise, offering reliable alternatives with improved detection capabilities. Nonetheless, further studies are still needed to validate their sensitivity and specificity to facilitate broader applications. This review explores the latest developments across diverse aptasensor types, including electrochemical, optical, and magnetic approaches, and examines their working principles, advantages, and limitations. It highlights the potential of aptasensors for practical applications in agricultural and environmental samples, emphasizing their role in advancing safety monitoring systems.

The objective was to evaluate the antimicrobial effects and possible mechanisms of action of extracts of Hibiscus sabdariffa calyxes and hibiscus acid (AH) on Campylobacter jejuni. The antimicrobial effect of extracts of H. sabdariffa calyxes (obtained with water, acetone, methanol, and ethanol) was evaluated alone and in a mixture with antibiotics using the paper disk technique. Possible damage to the membrane through permeability modification, leakage of genetic material and proteins, modification of zeta potential (ζ), electrophoretic mobility, pore formation, and the effect on biofilm formation was also investigated. The study found that extracts from H. sabdariffa calyxes, particularly the acetone extract (AE) and AH, effectively inhibited C. jejuni by damaging its membrane, causing leakage of genetic material and proteins, and altering zeta potential (ζ) and electrophoretic mobility. Both AE and AH also disrupted biofilm formation and induced membrane porosity. However, no synergistic effect was observed when combined with antibiotics. The findings suggest that these extracts could be potential alternatives to antibiotics for combating antibiotic-resistant C. jejuni.