Category Archives: Technology

Research – Mycotoxins and Essential Oils—From a Meat Industry Hazard to a Possible Solution: A Brief Review

MDPI

The preservation of food supplies has been humankind’s priority since ancient times, and it is arguably more relevant today than ever before. Food sustainability and safety have been heavily prioritized by consumers, producers, and government entities alike. In this regard, filamentous fungi have always been a health hazard due to their contamination of the food substrate with mycotoxins. Additionally, mycotoxins are proven resilient to technological processing. This study aims to identify the main mycotoxins that may occur in the meat and meat products “Farm to Fork” chain, along with their effect on the consumers’ health, and also to identify effective methods of prevention through the use of essential oils (EO). At the same time, the antifungal and antimycotoxigenic potential of essential oils was considered in order to provide an overview of the subject. Targeting the main ways of meat products’ contamination, the use of essential oils with proven in vitro or in situ efficacy against certain fungal species can be an effective alternative if all the associated challenges are addressed (e.g., application methods, suitability for certain products, toxicity). View Full-Text

Research – Microbial Control of Raw and Cold-Smoked Atlantic Salmon (Salmo salar) through a Microwave Plasma Treatment

MDPI

The control of the pathogenic load on foodstuffs is a key element in food safety. Particularly, seafood such as cold-smoked salmon is threatened by pathogens such as Salmonella sp. or Listeria monocytogenes. Despite strict existing hygiene procedures, the production industry constantly demands novel, reliable methods for microbial decontamination. Against that background, a microwave plasma-based decontamination technique via plasma-processed air (PPA) is presented. Thereby, the samples undergo two treatment steps, a pre-treatment step where PPA is produced when compressed air flows over a plasma torch, and a post-treatment step where the PPA acts on the samples. This publication embraces experiments that compare the total viable count (tvc) of bacteria found on PPA-treated raw (rs) and cold-smoked salmon (css) samples and their references. The tvc over the storage time is evaluated using a logistic growth model that reveals a PPA sensitivity for raw salmon (rs). A shelf-life prolongation of two days is determined. When cold-smoked salmon (css) is PPA-treated, the treatment reveals no further impact. When PPA-treated raw salmon (rs) is compared with PPA-untreated cold-smoked salmon (css), the PPA treatment appears as reliable as the cold-smoking process and retards the growth of cultivable bacteria in the same manner. The experiments are flanked by quality measurements such as color and texture measurements before and after the PPA treatment. Salmon samples, which undergo an overtreatment, solely show light changes such as a whitish surface flocculation. A relatively mild treatment as applied in the storage experiments has no further detected impact on the fish matrix.

Research – Antibiofilm Efficacy of Quercetin against Vibrio parahaemolyticus Biofilm on Food-Contact Surfaces in the Food Industry

MDPI

Vibrio parahaemolyticus, one of the most common foodborne pathogenic bacteria that forms biofilms, is a persistent source of concern for the food industry. The food production chain employs a variety of methods to control biofilms, although none are completely successful. This study aims to evaluate the effectiveness of quercetin as a food additive in reducing V. parahaemolyticus biofilm formation on stainless-steel coupons (SS) and hand gloves (HG) as well as testing its antimicrobial activities. With a minimum inhibitory concentration (MIC) of 220 µg/mL, the tested quercetin exhibited the lowest bactericidal action without visible growth. In contrast, during various experiments in this work, the inhibitory efficacy of quercetin at sub-MICs levels (1/2, 1/4, and 1/8 MIC) against V. parahaemolyticus was examined. Control group was not added with quercetin. With increasing quercetin concentration, swarming and swimming motility, biofilm formation, and expression levels of target genes linked to flagellar motility (flaAflgL), biofilm formation (vp0952vp0962), virulence (VopQvp0450), and quorum-sensing (aphAluxS) were all dramatically suppressed. Quercetin (0–110 μg/mL) was investigated on SS and HG surfaces, the inhibitory effect were 0.10–2.17 and 0.26–2.31 log CFU/cm2, respectively (p < 0.05). Field emission scanning electron microscopy (FE-SEM) corroborated the findings because quercetin prevented the development of biofilms by severing cell-to-cell contacts and inducing cell lysis, which resulted in the loss of normal cell shape. Additionally, there was a significant difference between the treated and control groups in terms of motility (swimming and swarming). According to our research, quercetin produced from plants should be employed as an antibiofilm agent in the food sector to prevent the growth of V. parahaemolyticus biofilms. These results indicate that throughout the entire food production chain, bacterial targets are of interest for biofilm reduction with alternative natural food agents in the seafood industry. View Full-Text

Research – Inhibitory Effect against Listeria monocytogenes of Carbon Nanoparticles Loaded with Copper as Precursors of Food Active Packaging

MDPI

Human listeriosis is a serious foodborne disease of which outbreaks are occurring increasingly frequently in Europe. Around the world, different legal requirements exist to guarantee food safety. Nanomaterials are increasingly used in the food industry as inhibitors of pathogens, and carbon nanomaterials are among the most promising. In the present study, novel carbon nanoparticles loaded with copper (CNP-Cu) were prepared, and their antimicrobial activity against Listeria monocytogenes was assessed. CNPs of two sizes were synthesized and characterized by dynamic light scattering (DLS), electrophoretic light scattering (ELS) and electron microscopy (EM). The minimum inhibitory concentration (MIC) of CNP-Cu was determined in accordance with the available standard. To get insights into its mechanism of action, the release of copper ions into a cell media was assessed by inductively coupled plasma optical emission (ICP-OE), and the ability of loaded CNPs to generate cytotoxic reactive oxygen species (ROS) was evaluated by EPR spectroscopy. Finally, the extent of release of copper in a food simulant was assessed. The results demonstrated the antimicrobial effectiveness of CNP-Cu, with growth inhibition up to 85% and a release of copper that was more pronounced in an acidic food simulant. Overall, the results indicate CNP-Cu as a promising agent for the design of active food packaging which is able to improve food shelf-life.

Research – Eco-Friendly Edible Packaging Systems Based on Live-Lactobacillus kefiri MM5 for the Control of Listeria monocytogenes in Fresh Vegetables

MDPI

To meet consumer requirements for high quality food free of chemical additives, according to the principles of sustainability and respect for the environment, new “green” packaging solutions have been explored. The antibacterial activity of edible bioactive films and coatings, based on biomolecules from processing by-products and biomasses, added with the bacteriocin producer Lactobacillus kefiri MM5, has been determined in vegetables against L. monocytogenes NCTC 10888 (i) “in vitro” by a modified agar diffusion assay and (ii) “on food” during storage of artificially contaminated raw vegetable samples, after application of active films and coatings. Both polysaccharides-based and proteins-based films and coatings showed excellent antilisterial activity, especially at 10 and 20 days. Protein-based films displayed a strong activity against L. monocytogenes in carrots and zucchini samples (p < 0.0001). After 10 days, both polysaccharide-based and protein-based films demonstrated more enhanced activity than coatings towards the pathogen. These edible active packagings containing live probiotics can be used both to preserve the safety of fresh vegetables and to deliver a beneficial probiotic bacterial strain. The edible ingredients used for the formulation of both films and coatings are easily available, at low cost and environmental impact.

Research – Pulsed light technology effectively kills harmful pathogens in new study

Science Daily

Novel food decontamination method inactivates pathogens like E. coli and Salmonella

A light-based, food sanitization technique successfully eliminated multiple harmful pathogens in a new study. The pulsed light technique shows promise as an effective alternative to the chemical, heat and water-based antimicrobial technologies commonly used in the food industry — and could be applicable more generally in sanitized environments such as hospitals, water treatment facilities and pharmaceutical plants, according to the researchers.

Researchers introduce rapid diagnostic test for Listeria

Phys Org

Researchers in the University of Georgia College of Engineering are developing a new way to detect potentially deadly Listeria contamination in food.

Listeriosis, an infection caused by eating food contaminated by the bacterium Listeria monocytogenes, can cause severe illness in pregnant women, newborns, the elderly and people with compromised immune systems. Listeria is the third leading cause of death from foodborne illness, or food poisoning, in the United States. An estimated 1,600 people get sick each year and about 260 die, according to the Centers for Disease Control and Prevention.

Currently, Listeria contamination in food products is identified only through molecular tests conducted in diagnostic laboratories on samples taken at specific control points during the manufacturing and distribution process. Although very accurate, this method requires significant processing time, transportation of samples, and expensive skilled labour and equipment.

In a new study published in the Journal of The Electrochemical Society, UGA researchers introduce a rapid diagnostic method based on electrochemical biosensing principles. Electrochemical biosensors are promising alternatives to molecular detection methods because of their ease of use, high specificity, sensitivity and low cost, according to the researchers.

The UGA researchers use bacteriophages, viruses that infect and replicate within bacteria, as bioreceptors to identify L. monocytogenes using an electrochemical sensor.

Research – Efficacy of 405 nm Light-Emitting Diode Illumination and Citral Used Alone and in Combination for Inactivation of Vibrio parahaemolyticus on Shrimp

MDPI

Vibrio parahaemolyticus is a widely distributed pathogen, which is frequently the lead cause of infections related to seafood consumption. The objective of the present study was to investigate the antimicrobial effect of the combination of 405 nm light-emitting diode (LED) and citral on V. parahaemolyticus. The antimicrobial effect of LED illumination and citral was evaluated on V. parahaemolyticus not only in phosphate-buffered saline (PBS) but also on shrimp. Quality changes of shrimp were determined by sensory evaluation. Changes in bacteria cell membrane morphology, cell membrane permeability, cell lipid oxidation level, and DNA degradation were examined to provide insights into the antimicrobial mechanism. The combination of LED treatments and citral had better antimicrobial effects than either treatment alone. LED combined with 0.1 mg/mL of citral effectively reduced V. parahaemolyticus from 6.5 log CFU/mL to below the detection limit in PBS. Combined treatment caused a 3.5 log reduction of the pathogen on shrimp within 20 min and a 6 log reduction within 2 h without significant changes in the sensory score. Furthermore, combined LED and citral treatment affected V. parahaemolyticus cellular morphology and outer membrane integrity. The profile of the comet assay and DNA fragmentation analysis revealed that combination treatment did not cause a breakdown of bacterial genomic DNA. In conclusion, LED may act synergistically with citral. They have the potential to be developed as novel microbial intervention strategies. View Full-Text

Research – Source of 7-year Listeria outbreak found in Germany

Food Safety News

German officials believe they have solved a seven-year Listeria outbreak that included the death of one man.

Using next generation sequencing (NGS) methods, the Bavarian State Office for Health and Food Safety (LGL) helped identify a likely connection between Listeria infections in Lower Bavaria and in the district of Altötting since 2015 and a food company.

The company was not named by authorities but they described it as a small businesses in the district of Passau that had various customers in the region. Local media reported it was a produce company that supplied canteens and care homes but not retailers.

Alongside the results from the NGS analysis, there are indications of an epidemiological connection to those sick based on the sales area.

Research – Impact of Industrial Practices on the Microbial and Quality Attributes of Fresh Vacuum-Packed Lamb Joints

MDPI

The impact of different industrial practices at lamb export abattoirs in Ireland on the microbial and quality attributes of fresh vacuum-packed (VP) lamb leg joints, including Clean Livestock Policy (CLP), fleece clipping, carcass chilling times and vacuum pack storage, at typical chill and retail display temperatures was investigated. Five separate slaughter batches of lamb (ranging in size from 38 to 60 lambs) were followed at two lamb export plants over a two-year period, accounting for seasonal variation. In general, fleece clipping resulted in significantly lower microbial contamination on the fleece than the use of CLP alone. Lamb from carcasses chilled for 24 h had significantly lower psychrophilic total viable counts and Brochothrix thermosphacta and pseudomonad counts than carcasses chilled for 72 h. Following vacuum-packed (VP) storage of meat from these carcasses at 1.7 ± 1.6 °C for 23 days in the meat plant followed by retail display at 3.9 ± 1.7 °C (up to day 50), the dominant microorganisms were lactic acid bacteria, Br. thermosphacta, Enterobacteriaceae and pseudomonads, and all had reached maximum population density by storage day 34. Aligned with this, after day 34, the quality of the raw meat samples also continued to deteriorate, with off-odours and colour changes developing. While the mean values for cooked meat eating quality attributes did not change significantly over the VP storage period, high variability in many attributes, including off-flavours and off-odours, were noted for lamb meat from all storage times, highlighting inconsistences in lamb quality within and between slaughter batches. View Full-Text