Category Archives: Food Technology

Research – Improving ready-to-eat apple cubes’ safety using chitosan-based active coatings

Posted on January 14, 2022 by | Leave a comment

Wiley Online

The use of active coatings is shown as an option to offer safe ready-to-eat fruits and respond the growing demand of consumers for fresh, environmentally friendly and products free from chemical preservatives. In this work, chitosan (Ch), chitosan + vanillin (Ch-V), and chitosan + geraniol (Ch-G) coatings were applied on apple cubes to evaluate their microbiological quality for 12 days of refrigerated storage. All combinations applied demonstrated significant bactericidal effects on native microbiota, resulting in number of mesophilics, psychrotrophics, and yeasts and molds under the detection limit (<2.00 log) immediately after coating and during 12 days for most of them. Moreover, Escherichia coli O157:H7 and Listeria innocua artificially inoculated on apple cubes showed great reductions after coating treatments, exerting vanillin or geraniol enriched coatings outstanding antimicrobial activity. In fact, after 12 days of refrigerated storage, apple cubes treated with vanillin and geraniol (>2.00 log CFU/g) showed reductions in E. coli O157:H7 counts greater than 2.00 log in comparison with the control (4.68 log CFU/g). The preliminary results of this study demonstrated that Ch, Ch-Va, and Ch-Ge could be an interesting alternative to improve the safety of apple cubes and, therefore, a novel option to offer safe, ready-to-eat apple to consumers.

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Posted in Decontamination Microbial, E.coli O157, E.coli O157:H7, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Listeria, Listeria invanovi, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research

CPS Funded Projects 2022 – Microbiology of Irrigation Water

Posted on January 8, 2022 by | Leave a comment

CPS

Microbial characterization of irrigation waters using rapid, inexpensive and portable next generation sequencing technologies

New microbial detection approaches utilizing whole genome sequencing are being increasingly applied for tracing microbial contaminants entering the food chain. The produce industry can directly benefit from powerful new methods such as shotgun metagenomics, which allows for the rapid identification of all the bacterial, viral, fungal, and protozoan pathogens in irrigation water, soil, or food samples in a single test. Furthermore, whole genome sequencing technologies are quickly becoming less expensive, and compact sequencing technologies like the Oxford Nanopore MinION device could potentially allow testing directly on-site in produce fields or other processing facilities for food safety surveillance programs. However, the application of these new whole genome sequencing technologies and approaches need to be verified and validated for use by the produce industry. The goal of this project is to investigate two technologies that offer slightly different approaches for pathogen detection, to identify the benefits and limitations of each, verify the results, and validate their applications by the produce industry for use in rapid pathogen detection in agricultural waters. The results of this study will provide recommendations, protocols and guidelines to the produce industry regarding the proper implementation of these technologies for pathogen surveillance.

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, WGS, Whole Genomic Sequencing

Research – Controlling Listeria monocytogenes Growth and Biofilm Formation using Flavonoids

Posted on January 6, 2022 by | Leave a comment

Journal of Food Protection

The aim of the present study was to investigate the ability of natural plant-derivate (flavonoid compounds) products to reduce and/or inhibit the biofilm-forming ability of Listeria monocytogenes. A collection of 500 synthetic and natural flavonoids were tested on strains of L. monocytogenes for their antimicrobial and anti-biofilm activity. L. monocytogenes biofilm inhibition by flavonoid compounds was tested on i) stainless steel coupons using crystal violet staining and ii) glass slides using confocal laser scanning microscopic (CLSM) imaging. The flavonoids were tested against a L. monocytogenes cocktail of 5 strains at a concentration of 100 µM to determine their effect on planktonic growth. A total of 17 flavonoids were chosen for further study due to their ability to significantly reduce the growth of L. monocytogenes in BHI broth, while 2 flavonoids were chosen because they actually increased growth. A lower concentration of flavonoid compounds (50 µM) was selected to investigate their effects on L. monocytogenes biofilm formation using i) stainless steel coupons to quantify biomass and ii) glass coupons to observe the biofilm architecture. The 19 flavonoids showed various levels of L. monocytogenes growth inhibition, ranging from 2% to 100%, as compared to the respective positive and negative controls on stainless steel, after 48 h of incubation at 22 o C. In addition, in comparison to the control, most of the 19 flavonoids significantly (p ≤ 0.05) inhibited biofilm formation, with at least one of the L. monocytogenes strains or at one of the tested temperatures. In fact, when grown in BHI broth with 50 µM of the 19 selected flavonoid compounds for 48 h at 22 o C, there were visible reductions in L. monocytogenes biofilm formation on the glass coupons. Overall, we found multiple flavonoid compounds to be promising anti-biofilm and antimicrobial agents against L. monocytogenes .

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Posted in Biofilm, Decontamination Microbial, Flavanoid, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Technology

CPS – Funded Projects 2022 – Superheated Steam – Process Surface Decontamination

Posted on January 5, 2022 by | Leave a comment

CPS

Practical application of superheated steam to harvesting, processing, and produce packing tools and equipment

Pathogens can contaminate environmental surfaces in produce handling operations. The industry uses sanitation programs to clean these surfaces and prevent product contamination. Highly effective sanitation procedures reduce the likelihood that pathogens will cross-contaminate products. In facilities that do not use water in their sanitation programs, tools like brushes and rags are used to clean. No-rinse sanitizers are sometimes used as well, but they cannot be used in organic operations. Superheated steam is a novel surface sanitizer that can kill pathogens on environmental surfaces. It is sometimes referred to as “dry steam” because it does not leave moisture or condensation on surfaces, making it a viable option for dry produce facilities. This project is designed to evaluate superheated steam use under industry relevant conditions. We will not only determine how well it works, but we will assess other key performance indicators including cost, range of appropriate applications, and the effect of extended use on equipment wear-and-tear and change to ambient relative humidity. This project will provide industry with the tools to comprehensively assess tradeoffs in superheated steam implementation. These resources will help improve the design of sanitation programs and enhance control over pathogen cross-contamination.

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Pathogen, pathogenic, Research

Research – Best Practice for the Control of Human Pathogenic Microorganisms in Plant Production Systems

Posted on January 4, 2022 by | Leave a comment

Teagasc

There is an increased emphasis on and observance of food-borne diseases associated with fresh produce, due in part to changes in the processing, agronomy and distribution of fresh produce but also in the increasing trend for the consumption of minimally processed and raw, ready-to-eat crops. A recent meeting of European experts and commercial growers, assembled under the HuPlant Cost Action assessed the current European situation in relation to the safety of horticultural produce under the themes of
(1) protecting fresh produce from microbial pathogens,
(2) control strategies and sampling and
(3) risk assessment and risk based sampling.
The following report details the discussions and observations which emanated from that meeting, including a list of recommendations, aimed at
(1) Growers,
(2) Regulators and Advisors and
(3) Scientists.
For growers recommendations include reinforcement through clear communication on the need to prevent initial contamination of produce through the adoption of good microbiological safety practice, utilising on farm risk assessments and a focus on avoidance of initial contamination rather than a reliance on decontamination efforts.
This can be achieved through approaches such as the adoption and incorporation of good agricultural practice and good hygiene into standard operating procedures on farm. Recommendations to regulators and advisors include balancing communication messages to growers, indicating what is required of them, but also equally, clearly explaining why it is necessary.
Additionally it was felt that additional supports and materials could be made available to growers, particularly to smaller growers, to assist in the training of staff on the importance of biological safety practice, particularly in sectors where staff turnover may be high and differences in the native languages spoken.
Finally recommendations to scientists include a greater emphasis on knowledge transfer and also to, where possible focus knowledge transfer efforts into developing clear recommendations which growers can implement. The interaction between the plant microbiome, potential pathogens, environmental conditions and agricultural practices requires a greater level of attention and research to aid in predict the risk of human pathogen establishment.
Overall it was recognised that through increased interaction and information exchange between stakeholders will enable better understanding of the issues and opportunities faced by the horticultural sector and the co-creation of advice through participation of all stakeholders can assist in reducing the risk of contamination of horticultural produce.

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Pathogen, pathogenic, Research, Technology

Research – Control of Bacillus weihenstephanensis in Pasteurized Liquid Whole Eggs Formulated with Nisin

Posted on January 3, 2022 by | Leave a comment

Journal of Food Protection

Bacillus weihenstephanensis can grow at refrigeration temperature and cause food poisoning. It has been isolated from liquid whole egg products. The moderate heat used for pasteurization of liquid egg products is ineffective for killing spore-forming bacteria including Bacillus. Available predictive models and a pretrial study in broth suggested the potential for growth of Bacillus spp. under the tested conditions. Hence, hurdles such as storage of product below 4°C or use of preservatives would be needed to ensure the food safety of pasteurized egg products. This study evaluated the growth inhibition of B. weihenstephanensis in pasteurized liquid whole egg product formulated with 6.25 ppm nisin during storage at refrigerated and abuse refrigerated temperatures for a total 13 weeks, in three replicate trials. At day 0, the product had a pH of 7.52±0.29, while background microflora such as aerobic plate counts, presumptive B. cereus, and yeast and molds were <10 CFU/g. Product inoculated with target 2.5 log10 CFU/g of B. weihenstephanensis, stored at 4°C for 4 weeks and subsequently at 7 or 10°C for 9 weeks exhibited no growth in all three replicate trials.  Average counts reduced (p<0.05) by at least one-log10 in six weeks in all samples stored at either 7 or 10°C. Similarly, growth of total plate counts, presumptive Bacillus spp., yeast and mold counts was not observed in uninoculated controls stored at 4°C for 4 weeks and subsequently at 7 or 10°C for 9 weeks. Visual and odor evaluation performed at each sampling time point showed no abnormalities. This study assessed the efficacy of maximum allowed level of nisin for use in pasteurized liquid whole eggs and validated the inhibition of B. weihenstephanensis in the product for an extended shelf life of up to 13 weeks.

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Posted in Bacillus, Bacillus weihenstephanensis, Decontamination Microbial, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Technology

Research – Survival of Salmonella Typhimurium and Escherichia coli O157:H7 on blueberries and impacts on berry quality during 12 weeks of frozen storage after washing with combinations of sodium dodecyl sulfate and organic acids or hydrogen peroxide

Posted on January 2, 2022 by | Leave a comment

Wiley Online

Salmonella spp. and Escherichia coli are well tolerant of freezing. This study was to investigate survival of the foodborne pathogens during storage at −18 ± 2°C for 12 weeks on blueberries after washing with: 500 ppm acetic acid plus 5,000 ppm sodium dodecyl sulfate (SDS) (AA/SDS), 20 ppm peroxyacetic acid plus 5,000 ppm SDS (PPA/SDS), or 200 ppm hydrogen peroxide plus 5,000 ppm SDS (H2O2/SDS), when compared with findings from no wash, or wash with water, 80 ppm PPA or 200 ppm chlorinated water. Following a 60 s contact with one of the three new solutions, the treatments showed 3.3–3.9 log10 CFU/g reductions in Salmonella Typhimurium and E. coli O157:H7 counts. After 2 weeks of frozen storage, 3.9–4.2 log10 CFU/g reductions of Salmonella and E. coli were observed. After 12 weeks of frozen storage, Salmonella and E. coli survivors were below detection limits (0.39 log10 CFU/g) in berries washed with new solutions. The frozen storage had a significant impact (p < .05) on microbial counts of both treated and nontreated blueberries. Although none of these washings decreased the total phenolic and anthocyanins contents and apparent quality at time 0, frozen storage caused significant damage on the texture of both treated and nontreated blueberries. Interestingly, no significant decrease in the total phenolic, anthocyanins content, and apparent quality was observed during the 12-week frozen storage. The counts of total bacteria, yeasts, and molds decreased throughout storage for treated and untreated berries. This demonstrates that the three wash solutions enhance the safety of frozen berries.

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Posted in Decontamination Microbial, E.coli, E.coli O157, E.coli O157:H7, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Salmonella

Research – Lactic Acid Bacteria as Antimicrobial Agents: Food Safety and Microbial Food Spoilage Prevention

Posted on January 1, 2022 by | Leave a comment

MDPI

In the wake of continual foodborne disease outbreaks in recent years, it is critical to focus on strategies that protect public health and reduce the incidence of foodborne pathogens and spoilage microorganisms. Currently, there are limitations associated with conventional microbial control methods, such as the use of chemical preservatives and heat treatments. For example, such conventional treatments adversely impact the sensorial properties of food, resulting in undesirable organoleptic characteristics. Moreover, the growing consumer advocacy for safe and healthy food products, and the resultant paradigm shift toward clean labels, have caused an increased interest in natural and effective antimicrobial alternatives. For instance, natural antimicrobial elements synthesized by lactic acid bacteria (LAB) are generally inhibitory to pathogens and significantly impede the action of food spoilage organisms. Bacteriocins and other LAB metabolites have been commercially exploited for their antimicrobial properties and used in many applications in the dairy industry to prevent the growth of undesirable microorganisms. In this review, we summarized the natural antimicrobial compounds produced by LAB, with a specific focus on the mechanisms of action and applications for microbial food spoilage prevention and disease control. In addition, we provide support in the review for our recommendation for the application of LAB as a potential alternative antimicrobial strategy for addressing the challenges posed by antibiotic resistance among pathogens. View Full-Text

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Posted in antimicrobial resistance, Antimicrobials, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, LAB, lactic acid bacteria, Lactobacillus, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus sakei, Lactobacillus saki, Lactococcus, microbial contamination, Microbiological Risk Assessment, Microbiology, Research

Research – A Naturally Derived Nanocomposite Film with Photodynamic Antibacterial Activity: New Prospect for Sustainable Food Packaging

Posted on December 30, 2021 by | Leave a comment

ACS

Abstract Image

Food packaging with efficient antibacterial ability is highly desirable and challenging in facing the crisis of microbial contamination. However, most present packaging is based on metal-based antibacterial agents and requires a time-consuming antibacterial process. Here, the unique packaging (CC/BB films) featuring aggregation-induced emission behavior and photodynamic inactivation activity is prepared by dispersing self-assembled berberine–baicalin nanoparticles (BB NPs) into a mixed matrix of sodium carboxymethylcellulose-carrageenan (CC). The superiority of this design is that this packaging film can utilize sunlight to generate reactive oxygen species, thus eradicating more than 99% of E. coli and S. aureus within 60 min. Also, this film can release BB NPs to inactivate bacteria under all weather conditions. Surprisingly, the CC/BB nanocomposite film presented excellent mechanical performances (29.80 MPa and 38.65%), hydrophobicity (117.8°), and thermostability. The nanocomposite film is validated to be biocompatible and effective in protecting chicken samples, so this work will provide novel insights to explore safe and efficient antibacterial food packaging.

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Posted in Decontamination Microbial, E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Staphylococcus aureus, Technology

Research – ‘Jelly’ ice cubes could revolutionize cold storage and the safety of cold food

Posted on December 30, 2021 by | Leave a comment

Food Safety News

Researchers at the University of California-Davis have developed a new type of cooling cube with the potential, they say, to transform how cold storage is done.

The benefits of plastic-free, “jelly ice cubes” are that they do not melt, are compostable and antimicrobial, and can help prevent cross-contamination.

It can be easy for foodservice operators and their employees not to think about the food safety implications of how ice is used and handled. If they don’t take proper precautionary measures to handle food properly or keep up with necessary preventive maintenance measures to ensure that their ice machines are clean, sanitary and operating safely, there can be serious food safety risks. The researchers at the UC-Davis took note of this concern.

The researchers began working on their coolant cubes after Luxin Wang, an associate professor in the Department of Food Science and Technology, saw the amount of ice used at fish-processing plants and the cross-contamination that meltwater could spread among products or drains.

“The amount of ice used by these fish-processing sites is massive,” Wang said. “We need to control the pathogens.”

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Safety, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Technology