Category Archives: Food Technology

Research – From Germination to Stagnation: Sodium Diacetate’s Impact on Clostridium perfringens Spores

Wiley Online

ABSTRACT

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.

Research – Simple lab-free test to detect bacteria in fluids from water to urine

Science Daily

A novel new test for bacteria in fluids makes it as easy as observing a colour change to confirm the presence of disease-causing pathogens, promising much easier diagnostic tests and greater food safety.

Engineers and biochemists at McMaster university have brought their skills together to make it possible for untrained users to confirm contamination in fluids using a biogel test that changes colour in the presence of such bacteria as E. coli, listeria and other frequent testing targets.

The test uses harmless bacteriophages embedded in the gel to locate target bacteria in a sample of fluid such as lake water, urine or a container of milk, even in low concentrations.

Bacteriophages are the most common form of life on Earth. Each form of bacteriophage is specialized to destroy one form of bacteria.

Research – Isolation and Detection of the Emerging Pathogen Escherichia albertii in Clinical Stool Samples and the Potential Transmission by Meat Samples in Retail

MDPI

Abstract

The significance of Escherichia albertii as a foodborne pathogen is increasingly acknowledged, but the assessment of its occurrence and transmission remains challenging due to the lack of validation of selective isolation, detection, and identification methods. The aim of the present study was to examine its presence on various meat samples at the retail level in order to assess a potential foodborne transmission and its occurrence in clinical stool samples. First, the evaluation and selection of a selective enrichment broth and isolation medium, combined with an optimized identification by MALDI-TOF MS, as well as a suitable DNA extraction method and a PCR-based detection strategy were developed. After the evaluation of existing isolation strategies and the formulation of an adapted enrichment and isolation medium, 100% isolation specificity was not achieved. An identity confirmation of suspected colonies remains necessary. A total of 292 samples, including 45 beef fillet, 51 minced beef, 50 pork fillet, 30 minced pork, 30 chicken carcass, 51 chicken fillet, and 35 minced chicken samples were examined. Samples were all collected at the retail level, including supermarkets and local butcheries. Escherichia albertii was isolated from two chicken fillets (3.9%) and additionally detected in one minced chicken (4.5%) and two other chicken fillet (4.5%) samples by a PCR assay. All beef and pork samples tested negative for its presence, but transmission through these meat types cannot be excluded, as it potentially correlates with the level of fecal contamination that was significantly higher on poultry products. With other hygienic conditions and processing steps applied, the presence of E. albertii on food can therefore differ in other parts of the world. Escherichia albertii was present in 0.4% of the 2419 clinical stool samples examined. The future development of a chromogenic isolation medium, as well as further extensive epidemiologic approaches and a genomic comparison of human, food, and animal isolates, could enhance the assessment of the emerging pathogen status and its potential as a foodborne hazard.

Research – Cold Plasma and Pulsed Light Inactivates Escherichia coli O157: H7 in Romaine Lettuce and Preserves Produce Quality

Wiley Online

ABSTRACT

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.

Research – Popular air fryers could be a food safety risk if you don’t ‘Look before you cook’ Australian Food Safety Week 9-16 November 2024

Food Safety Information Council

This Australian Food Safety Week 9 to 16 November, the Food Safety Information Council is advising consumers that air fryers could be a food safety risk if they don’t follow cooking instructions.

Lydia Buchtmann, the Council’s CEO, said that air fryers are becoming very popular with our recent research shows 2 in 3 Australians surveyed have an air fryer in their household, with 54% of those using it weekly and 38% several times a week.

‘Air fryers are convenient and easy to use, but there have been individual foodborne disease cases around the country linked to air fryers, especially when cooking crumbed products that may look cooked on the outside but aren’t fully cooked on the inside.

Research – EPA Approves First Antimicrobial Treatment of Foodborne Pathogens in Preharvest Agricultural Water

Food Safety.com

The first-ever registration of an antimicrobial treatment for foodborne pathogens in preharvest agricultural water has been approved by the U.S. Environmental Protection Agency (EPA), setting a new precedent for preharvest agricultural water treatments specifically intended to reduce the presence of pathogens that affect food safety.

The successful registration of SANIDATE 12.0 is the result of a collaborative effort between EPA and the U.S. Food and Drug Administration (FDA) to develop and refine an efficacy protocol to support such registrations. Using the revised efficacy protocol, the University of Arizona and industry members worked together to register SANIDATE 12.0 for use against foodborne pathogens like Escherichia coli and Salmonella in preharvest agricultural water, and to provide feedback on the protocol that informed updates regarding testing parameters and to clarify the protocol for future users.

Research – Antibacterial Activity of Phloretin Against Vibrio parahaemolyticus and Its Application in Seafood

MDPI

Abstract

Although phloretin is widely utilized in the food industry as an additive, its effects on foodborne pathogens remain insufficiently investigated. This study aimed to evaluate the antimicrobial properties of phloretin (PHL) against Vibrio parahaemolyticus (V. parahaemolyticus) and to elucidate the potential mechanisms of action. After PHL treatment, alterations in the cell morphology, cell microstructure, and intracellular contents of V. parahaemolyticus were assessed. Scanning electron microscopy revealed substantial damage to cell integrity, subsequent to PHL treatment. A notable reduction in intracellular components, including proteins, ATP, and DNA, was observed in samples treated with PHL. PHL was shown to inhibit the activities of ATPase, β-galactosidase, and respiratory chain dehydrogenase in V. parahaemolyticus. Furthermore, it was demonstrated to elevate the intracellular levels of reactive oxygen species and promote cell death. After being applied to sea bass, shrimp, and oysters, PHL effectively inactivated V. parahaemolyticus in these seafoods. These findings demonstrate that PHL has potential for application in seafood to control V. parahaemolyticus.

Research – Effects of Combined Cold Plasma and Organic Acid-Based Sanitizer Treatments Against Salmonella enterica on Tomato Surfaces

Wiley Online

ABSTRACT

Incidence of foodborne illness due to bacterial contamination of fresh produce continue to exist despite continuous research on processing interventions to mitigate the problem. In this study, we combined atmospheric cold plasma treatments with an antimicrobial solution containing specific organic acids generally recognized as safe (GRAS) by the FDA and tested its antimicrobial efficacy against Salmonella enterica inoculated on tomato surfaces. Tomato surfaces were inoculated with at 5.6 log CFU/g of Salmonella by spotting 0.1 mL of 7 log CFU/ml Salmonella onto the tomato stem scars, and by dipping whole tomatoes into a solution of 7 log CFU/ml Salmonella for 3 min to achieve 4.1 log CFU/g. Antimicrobial efficacy of the organic acid-based sanitizer + cold plasma treatments for 30, 60, 120, 180, and 360 s, were investigated, and significant bacterial inactivation was achieved above 120 s treatments. At 120 s, surviving populations of aerobic mesophilic bacteria recovered on the tomatoes surfaces averaged < 2 logs/g while yeast and mold survival averaged < 1 CFU/g. Treatment combination with this organic acid-based sanitizer + cold plasma for 120 s resulted in a 4.9 log reduction of Salmonella on the stem scar area and a 3.9 log reduction on the smooth peel surface. Similarly, populations of aerobic mesophilic bacteria recovered on treated tomato surfaces averaged < 0.3 log CFU/g. The results of this study indicate that combining an organic acid-based sanitizer with cold plasma treatments for ≥ 120 s can inactivates significant populations of Salmonella to enhance the microbial safety of tomato surfaces designated for fresh-cut salad.

Researchers pioneer nanotechnology to combat E. coli in rice, strengthen food safety

Food Safety News

Researchers at the University of Texas at El Paso (UTEP) have made a major breakthrough in agricultural biotechnology, focusing on the use of nanotechnology to combat E. coli contamination in rice crops. This discovery, led by Hamidreza Sharifan and his team, offers promising solutions for improving food safety and addressing bioterrorism threats.

The research centers on the development of advanced methods to detect and mitigate the effects of pathogens, particularly E. coli, which poses a significant threat to global food systems. The team, which includes Daisy Wilson, a Ph.D. student in environmental science and engineering, and Valeria Gonzalez, a senior undergraduate in forensic science, conducted groundbreaking work in biofortification and nanoparticle application to reduce microbial contamination.

“We got an internship with the Department of Homeland Security as a team,” Wilson told The Prospector, UTEP’s student newspaper. “It was led by Dr. Sharifan, and he mentored myself and Valeria for the summer.”

Research – Impact of Various Washing Protocols on the Mitigation of Escherichia coli Contamination in Raw Salad Vegetables

MDPI

Vegetables are an essential component of a balanced diet. The consumption of ready-to-eat foods may lead to the risk of infections and illnesses due to microbial contamination. To mitigate the potential of microbial contamination risks, it is critical to promote safe handling practices among consumers. In this study, our research evaluated the efficacy of different vegetable washing methods, specifically with lettuce, tomato, and cucumber, to establish optimal practices for reducing microbial contamination. This study consisted of two phases. Initially, a survey was distributed to 150 volunteers using snowball sampling to assess everyday vegetable handling and washing methods. The survey’s results identified four predominant methods: washing with a 5% vinegar solution for 3 min followed by tap water rinse (37.3% of participants), rinsing with tap water for 1 min (29.3%), washing with a 5% salt solution (vegetable soap) for 3 min followed by a tap water rinse (16.6%), and a 3 min tap water rinse (14%). A minor segment (3.33%) reported not washing their vegetables at all. The survey’s findings guided the second phase, which tested the aforementioned washing protocols’ effectiveness in reducing Escherichia coli (E. coli) levels on spiked contaminated salad vegetables. The tested vegetables were sterilized using UV light, inoculated with 0.5 McFarland E. coli, and then washed using the four identified methods. After that, E. coli enumeration after washing was performed using 3M™ Petrifilm and the comparison was analyzed via one-way ANOVA. During this study, it was revealed that the cucumbers had the highest E. coli contamination levels in comparison to the lettuce and tomato after washing. Interestingly, by comparing the three washing methods, it was found that washing the vegetables with vinegar proved to be the most effective solution for reducing microbial presence on both lettuce and cucumbers. Notably, the natural smoothness of tomato skin led to no significant differences in contamination levels across washing methods. In summary, vinegar washing effectively reduces microbial contamination from salad vegetables, highlighting the need for informed consumer practices to prevent foodborne outbreaks. This study emphasizes the importance of monitoring contamination sources and using safe washing techniques.