Category Archives: Technology

Research – Evaluation of Hygiene Indicators and Sampling Plan for Detecting Microbial Contamination in Health Functional Foods

Posted on April 2, 2022 by | Leave a comment

Journal of Food Protection

This study aimed to monitor microbial contamination level in a variety of health functional foods and to establish new microbial criteria. Indicator organisms (i.e., aerobic bacteria, coliform bacteria, and Escherichia coli ) were monitored in 10 health functional food categories (743 items, 3,715 samples). The mean total aerobic counts of ginseng and Korean red ginseng were -0.35 and -0.74 log10 CFU/g; and their mean total coliform counts were -1.4 and -1.39 log10 CFU/g, respectively. In addition, the mean total coliform counts of fiber and protein products were -1.34 and -1.22 log10 CFU/g, respectively. However, no aerobic or coliform cells were detected in any other health functional food products (vitamins, minerals, probiotics, milk thistle extract, propolis, eicosapentaenoic acid, docosahexaenoic acid, or lutein products), and no E. coli was detected in any of the categories. These results can potentially be used to update the microbial criteria of the Health Functional Food Code.

Leave a comment

Posted in Coliforms, 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, Technology

Research – Inhibition of Listeria monocytogenes by Phage Lytic Enzymes Displayed on Tailored Bionanoparticles

Posted on March 31, 2022 by | Leave a comment

MDPI

The high mortality rate associated with Listeria monocytogenes and its ability to adapt to the harsh conditions employed in food processing has ensured that this pathogen remains a serious problem in the ready-to-eat food sector. Bacteriophage-derived enzymes can be applied as biocontrol agents to target specific foodborne pathogens. We investigated the ability of a listeriophage endolysin and derivatives thereof, fused to polyhydroxyalkanoate bionanoparticles (PHA_BNPs), to lyse and inhibit the growth of L. monocytogenes. Turbidity reduction assays confirmed the lysis of L. monocytogenes cells at 37 °C upon addition of the tailored BNPs. The application of BNPs also resulted in the growth inhibition of L. monocytogenes. BNPs displaying only the amidase domain of the phage endolysin were more effective at inhibiting growth under laboratory conditions (37 °C, 3 × 107 CFU/mL) than BNPs displaying the full-length endolysin (89% vs. 83% inhibition). Under conditions that better represent those found in food processing environments (22 °C, 1 × 103 CFU/mL), BNPs displaying the full-length endolysin demonstrated a greater inhibitory effect compared to BNPs displaying only the amidase domain (61% vs. 54% inhibition). Our results demonstrate proof-of-concept that tailored BNPs displaying recombinant listeriophage enzymes are active inhibitors of L. monocytogenes. View Full-Text

Leave a comment

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

Research – Enhanced antimicrobial effectiveness of synergistic mixtures of rambutan peel extract and cinnamon essential oil on food spoilage bacteria and bio-based food packaging

Posted on March 31, 2022 by | Leave a comment

Wiley Online

Staph

This research aims to enhance antimicrobial activity of rambutan peel extract (RPE), by mixing with cinnamon essential oil (CEO). The mixture of RPE and CEO with different weight ratios (10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, and 0:10) had been prepared and the antimicrobial efficacy was tested. Nine strains of bacteria: Gram-positive bacteria (Bacillus sp., Enterococcus faecalis, Leuconostoc sp., Micrococcus luteus, Staphylococcus aureus, and Streptococcus sp.) and Gram-negative bacteria (Escherichia coli, Pseudomonas fluorescens, and Salmonella typhimurium) were selected as the representative of pathogenic and food spoilage bacteria. Mixing RPE with CEO in a ratio of 5:5 showed the best synergistic effect against those bacteria. Addition of RPE/CEO in a weight ratio of 5:5 improved the antimicrobial activity of whey protein isolated (WPI) films, and enhanced strength, stiffness, and water resistance of the film.

Leave a comment

Posted in Bacillus, Decontamination Microbial, E.coli, Faecal Streptpcocci, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Pseudomonas fluorescens, Research, Salmonella, Staphylococcus aureus, Technology

Research – Novel Salmonella Phage, vB_Sen_STGO-35-1, Characterization and Evaluation in Chicken Meat

Posted on March 20, 2022 by | Leave a comment

MDPI

Salmonellosis is one of the most frequently reported zoonotic foodborne diseases worldwide, and poultry is the most important reservoir of Salmonella enterica serovar Enteritidis. The use of lytic bacteriophages (phages) to reduce foodborne pathogens has emerged as a promising biocontrol intervention for Salmonella spp. Here, we describe and evaluate the newly isolated Salmonella phage STGO-35-1, including: (i) genomic and phenotypic characterization, (ii) an analysis of the reduction of Salmonella in chicken meat, and (iii) genome plasticity testing. Phage STGO-35-1 represents an unclassified siphovirus, with a length of 47,483 bp, a G + C content of 46.5%, a headful strategy of packaging, and a virulent lifestyle. Phage STGO-35-1 reduced S. Enteritidis counts in chicken meat by 2.5 orders of magnitude at 4 °C. We identified two receptor-binding proteins with affinity to LPS, and their encoding genes showed plasticity during an exposure assay. Phenotypic, proteomic, and genomic characteristics of STGO-35-1, as well as the Salmonella reduction in chicken meat, support the potential use of STGO-35-1 as a targeted biocontrol agent against S. Enteritidis in chicken meat. Additionally, computational analysis and a short exposure time assay allowed us to predict the plasticity of genes encoding putative receptor-binding proteins.

Leave a comment

Posted in Bacteriophage, 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, Salmonella, Technology

Research – Biofilm through the Looking Glass: A Microbial Food Safety Perspective

Posted on March 14, 2022 by | Leave a comment

MDPI

Food-processing facilities harbor a wide diversity of microorganisms that persist and interact in multispecies biofilms, which could provide an ecological niche for pathogens to better colonize and gain tolerance against sanitization. Biofilm formation by foodborne pathogens is a serious threat to food safety and public health. Biofilms are formed in an environment through synergistic interactions within the microbial community through mutual adaptive response to their long-term coexistence. Mixed-species biofilms are more tolerant to sanitizers than single-species biofilms or their planktonic equivalents. Hence, there is a need to explore how multispecies biofilms help in protecting the foodborne pathogen from common sanitizers and disseminate biofilm cells from hotspots and contaminate food products. This knowledge will help in designing microbial interventions to mitigate foodborne pathogens in the processing environment. As the global need for safe, high-quality, and nutritious food increases, it is vital to study foodborne pathogen behavior and engineer new interventions that safeguard food from contamination with pathogens. This review focuses on the potential food safety issues associated with biofilms in the food-processing environment. View Full-Text

Leave a comment

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

Research – High-pressure processing: food safety without compromising quality

Posted on March 9, 2022 by | Leave a comment

EFSA

High-pressure processing (HPP) of food is effective at destroying harmful microorganisms and poses no more food safety concerns than other treatments. These are two of the conclusions of a scientific opinion published by EFSA today.

EFSA experts assessed the safety and efficacy of HPP of food and, more specifically, whether it can be used to control Listeria monocytogenes in ready-to-eat (RTE) foods and as an alternative to thermal pasteurisation of raw milk.

HPP is a non-thermal food preservation technique that kills microorganisms that can cause diseases or spoil food. It uses intense pressure for a certain time and has minimal effects on taste, texture, appearance, or nutritional values.

HPP can be used at different steps of the food chain, usually on pre-packed products. It can be applied to raw materials such as milk, fruit juices, and smoothies but also to products that have already been processed, such as sliced cooked meat products and RTE meals. In the latter case, it reduces the contamination originating from the manufacturing environment, for example during slicing and manipulation of the products.

This processing method reduces levels of Listeria monocytogenes in RTE meat products, at specific time-pressure combinations defined in the scientific opinion. In general, the longer the duration and intensity of the pressure, the more reduction is achieved. This is an important finding because L. monocytogenes contamination of RTE foods is a public health concern in the EU. HPP also proved to be effective at decreasing the levels of other pathogens, such as Salmonella and E. coli.

For raw milk, experts identified the time-pressure combinations that can be considered to have the same effect as thermal pasteurisation. These vary depending on the pathogen considered.

HPP is not specifically regulated at EU level and EFSA’s advice will inform the possible decisions of risk managers in this field.

Leave a comment

Posted in Decontamination Microbial, EFSA, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Safety, food safety training, Food Technology, HPP, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microorganism DNA, Technology

Research – The Efficacy of Conventional Spray, Electrostatic Spray, and Dip with a Combination of Hydrogen Peroxide and Peroxyacetic Acid to Inactivate Listeria monocytogenes on Apples

Posted on February 23, 2022 by | Leave a comment

Journal of Food Protection

This study aimed to evaluate the efficacy of a and hydrogen peroxide (H 2 O 2 ) and peroxyacetic-acid (PAA) mixer delivered by conventional garden sprayer (GS), electrostatic sprayer (ES) and dip methods to inactivate Listeria monocytogenes on apples. Organic Honey Crisp ( HC ), Fuji ( FJ ), and Pink Lady ( PL ) were dip-inoculated with Listeria monocytogenes (2-strain, serotype 1/2b), which were then kept untreated (control), sprayed with water only, or treated with the H 2 O 2 -PAA mixer (0.0064, 0.1, 0.25 and 0.50%) for 20 s via GS, ES, or dip, followed by draining (2 min) on aluminum foil. Surviving bacteria were recovered on Modified Oxford agar. Atomic force microcopy was used to detect the structural changes of inactivation of L. monocytogenes in broth medium by the H 2 O 2 -PAA mixer solution. Data (2 replicates/6 samples/replicate) were analyzed using the Mixed Model Procedure of SAS ( P =0.05). Initial counts of L. monocytogenes on untreated apples were 6.80 to 6.90 log CFU/apple. The dip method was the most effective treatment (P<0.05) on pathogen reductions (2.31-2.41 log CFU/apple) followed by GS (1.44-1.70 log CFU/apple) and then ES (0.84-1.20 log CFU/apples). Reductions of L. monocytogenes were greatest ( P < 0.05) when apples were treated with H 2 O 2 -PAA mixer -0.25 and -0.50%. Atomic force microscopy analyses indicated that inactivation of L. monocytogenes cells in H2O2-PAA mixer solutions resulted from disruption of the outer membrane. The H 2 O 2 -PAA mixer treated cells had increased width, height and decreased roughness when compared to the untreated cells. Results suggested that applying a H 2 O 2 -PAA mixer by dip or GS methods is better for pathogen reduction than ES on apples.

Leave a comment

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

Research – Antibacterial Properties of TMA against Escherichia coli and Effect of Temperature and Storage Duration on TMA Content, Lysozyme Activity and Content in Eggs

Posted on February 20, 2022 by | Leave a comment

MDPI

Studies on trimethylamine (TMA) in egg yolk have focused on how it impacts the flavor of eggs, but there has been little focus on its other functions. We designed an in vitro antibacterial test of TMA according to TMA concentrations that covered the TMA contents typically found in egg yolk. The change in TMA content in yolk was analyzed at different storage temperatures and for different storage durations. The known antibacterial components of eggs, including the cuticle quality of the eggshell and the lysozyme activity and content in egg white, were also assessed. The total bacterial count (TBC) of different parts of eggs were detected. The results showed that the inhibitory effect of TMA on Escherichia coli (E. coli) growth increased with increasing TMA concentration, and the yolk TMA content significantly increased with storage duration (p < 0.05). The cuticle quality and lysozyme content and activity significantly decreased with storage time and increasing temperature, accompanied by a significant increase in the TBC on the eggshell surface and in the egg white (p < 0.05). This work reveals a new role for trace TMA in yolks because it reduces the risk of bacterial colonization, especially when the antibacterial function of eggs is gradually weakened during storage.

Leave a comment

Posted in Antibacterial, Antimicrobials, Decontamination Microbial, E.coli, escherichia 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, Technology

Research – Microbial safety and sanitary quality of strawberry primary production in Belgium: risk factors for Salmonella and Shiga toxin producing Escherichia coli (STEC) contamination.

Posted on February 19, 2022 by | Leave a comment

AEM

Hepatitis A kswfoodworld

Strawberries are an important fruit in Belgium both in production and consumption, but little information is available about the presence of Salmonella and STEC in these berries, the risk factors in agricultural production and possible specific mitigation options. In 2012, a survey was undertaken of three soil and three soilless cultivation systems in Belgium. No Salmonella spp. was isolated. No STEC was detected in the strawberry samples (0 out of 72), but STEC was detected by qPCR in 11 out of 78 irrigation water and 2 out of 24 substrate samples.

Culture isolates were obtained for 2 out of 11 qPCR positive irrigation water samples and 2 out of 2 substrate samples. Multivariable logistic regression analysis revealed elevated generic E. coli numbers (odds ratio (OR) for 1 log increase being 4.6) as the most important risk factor for STEC, together with the berry picking season (elevated risk in summer).

Presence of generic E. coli in the irrigation water (≥ 1 cfu per 100 ml) was mainly influenced by the type of irrigation water (collected rainfall water stored in ponds was more often contaminated than ground water pumped from boreholes (OR = 5.8)) and the lack of prior treatment (untreated water versus water subjected to sand filtration prior to use (OR = 19.2)).

The follow-up study in 2013 at one of the producers indicated cattle as the most likely source of STEC contamination of the irrigation water.

Leave a comment

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, Salmonella, STEC, STEC E.coli, Technology

Research – Effect of hydrophobic/hydrophilic characteristics of B. cereus spores on their resistance to detergents

Posted on February 12, 2022 by | Leave a comment

Journal of Food Protection

Bacillus cereus spores have the ability to adhere to solid surfaces, including stainless steel, a material widely used in food industries. Adhesion of spores allows for recontamination during food processing, and the cleaning and disinfection are largely used by industries to control them. Hence, this study aims to assess the detachment capacity (or removing activity) of sodium hydroxide, nitric acid, phosphoric acid-based detergent, chlorine-based detergent; against two adhered Bacillus cereus spores (hydrophobic strain and hydrophilic strain) to stainless steel surfaces. Microorganism adhesion on the surfaces reached 5.5 log CFU/cm² the two strain studied. Two protocols composed of combinations of chemical compounds concentration, temperature, and contact time were tested. The inactivation kinetics shapes were convex and were modelled by the Weibull model. The effect of temperature and biocide concentration were quantified using a Bigelow like model. The temperature applied during of treatment of the cleaning in place is an important factor acting on the speed of inactivation or detachment of Bacillus cereus spores. However, this efficiency depends on the hydrophobic characteristics of Bacillus cereus spores. The concentration of detergent and acid also affects the inactivation rate. The inactivation rate, whereas the character of hydrophobic does not intervene for the chlorine alkaline treatments.

Leave a comment

Posted in Bacillus, Bacillus cereus, 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, Technology