Category Archives: Food Microbiology Research

Research – UV-C LED Irradiation Reduces Salmonella on Chicken and Food Contact Surfaces

Posted on June 24, 2021 by | Leave a comment

MDPI

Ultraviolet (UV-C) light-emitting diode (LED) light at a wavelength of 250–280 nm was used to disinfect skinless chicken breast (CB), stainless steel (SS) and high-density polyethylene (HD) inoculated with Salmonella enterica. Irradiances of 2 mW/cm2 (50%) or 4 mW/cm2 (100%) were used to treat samples at different exposure times. Chicken samples had the lowest Salmonella reduction with 1.02 and 1.78 Log CFU/cm2 (p ≤ 0.05) after 60 and 900 s, respectively at 50% irradiance. Higher reductions on CB were obtained with 100% illumination after 900 s (>3.0 Log CFU/cm2). Salmonella on SS was reduced by 1.97 and 3.48 Log CFU/cm2 after 60 s of treatment with 50% and 100% irradiance, respectively. HD showed a lower decrease of Salmonella, but still statistically significant (p ≤ 0.05), with 1.25 and 1.77 Log CFU/cm2 destruction for 50 and 100% irradiance after 60 s, respectively. Longer exposure times of HD to UV-C yielded up to 99.999% (5.0 Log CFU/cm2) reduction of Salmonella with both irradiance levels. While UV-C LED treatment was found effective to control Salmonella on chicken and food contact surfaces, we propose three mechanisms contributing to reduced efficacy of disinfection: bacterial aggregation, harboring in food and work surface pores and light absorption by fluids associated with CB. View Full-Text

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Research, Salmonella, Salmonella in Chicken, UV Microbiology

USA – FDA Core Investigation Table Update

Posted on June 24, 2021 by | Leave a comment

FDA

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research

Norway – Research – Risk ranking and source attribution of food- and waterborne pathogens for surveillance purposes – Toxoplasma the top risk!

Posted on June 23, 2021 by | Leave a comment

VKM

Toxoplasma

Background
Providing risk managers with the information that they need for decision making is an important element in food-safety management. The present risk assessment was undertaken to establish a scientific basis that could be used to assist the Norwegian Food Safety Authority (NFSA) in implementing risk-based surveillance, monitoring, and control programmes for pathogens in food and water. The assessment approach used here consisted of two steps:(1) risk ranking of 20 selected pathogens based on the incidence and severity of their associated diseases following infection with the pathogens via food or water, and(2) a source attribution process aimed at identifying the main pathogen-food combinations that may pose a risk to human health for each of the ranked pathogens. We used an expert knowledge elicitation (EKE) procedure with a panel of nine experts, including all eight members of the Panel on Biological Hazards of the Norwegian Scientific Committee for Food and Environment (NSCFE) and one invited expert on food/water-borne viral infections.
Risk Ranking
The 20 pathogens selected for risk ranking were defined in the terms of reference (ToR) received from NFSA. We performed a multicriteria-based ranking of the pathogens in terms of their public health impact from food/water-borne transmission in Norway. The risk ranking utilized six criteria that estimated the incidence of food- and waterborne illness attributable to each pathogen, the severity of acute and chronic illness, the fraction of chronic illness, fatality rate, and the probability for future increased disease burden. For each pathogen, all criteria were scored by the expert panel members, and individual criterion scores were combined into an overall score for every pathogen. To achieve this, each criterion was weighted in terms of its relative importance, as judged by the expert panel. The overall scores so calculated were the basis for the ranking.
Source attribution
For each of the ranked pathogens, the subsequent source-attribution process aimed to identify the main food vehicles, reservoirs, and sources of infection for outbreak-related and sporadic cases of illness, the relative importance of food sources, and preventable risk factors in Norway. To achieve this, both microbiological and epidemiological data were scrutinized. These encompassed results from national surveillance and monitoring programmes, prevalence surveys, outbreak investigations, and research, including analytic epidemiological studies. When Norwegian data were sparse or absent, international reports and research were used.
Results
The six highest-ranked pathogens were, in descending order: Toxoplasma gondii, Campylobacter spp., Echinococcus multilocularis, enterohaemorrhagic E. coli (EHEC), Listeria monocytogenes, and non-typhoid Salmonella. It should be emphasized, however, that confidence intervals revealed considerable overlaps between the scores. The food vehicles associated with the pathogens varied widely. It is notable, however, that fresh produce was identified as being among the main food vehicles for 12 of the 20 pathogens, drinking water was associated with 8, and 5 were linked to raw milk or products thereof

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Posted in Campylobacter, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Pathogen, pathogenic, Research, Salmonella, Toxoplasma gondii, Toxoplasmosis

UK – Almost half the adults (46%) who cook coated frozen chicken products do not always check cooking instructions on packaging before cooking

Posted on June 22, 2021 by | Leave a comment

FSA

The Food Standards Agency (FSA), Food Standards Scotland (FSS) with Ipsos MORI have published a survey of consumer practices relating to coated frozen chicken products.

This survey identifies behaviours which could increase people’s risk to foodborne disease. It was commissioned as a result of a Salmonella incident linked to frozen chicken products such as nuggets, goujons, dippers, poppers and kievs. While these products may appear cooked on the outside, they often contain raw chicken and so they must be cooked thoroughly to help kill Salmonella bacteria.

Findings show that two thirds of adults aged 16-75 (67%) say they have recently cooked or eaten coated frozen chicken products at home. These products are particularly popular with younger adults, with 88% of those aged 16-24 having recently consumed them or cooked them at home. Participants were also more likely to have cooked or eaten these products if they have children aged 15 or under in their household (86%).

The survey also included questions on the storage and handling of these products pre and post-cooking:

  • Almost two thirds of those who cook these products (62%) say uncooked coated frozen chicken products at least sometimes come into contact with other surfaces such as worktops and plates
  • Over half of those who cook these products (58%) say they always wash their hands after handling coated frozen chicken products
  • Almost a quarter of consumers who personally cook products say they defrost them before cooking (23%), 62% say they do not. Among those who defrost products, half say they leave them at room temperature (53%)

Most participants who use an oven to cook coated frozen chicken products say they sometimes cook them together with other products, such as chips or vegetables (84%). Cooking these chicken products at a lower temperature or for a shorter time than advised may mean they are not thoroughly cooked before serving.

Narriman Looch, Head of Animal Feed and Foodborne Disease Control Branch said: ‘It’s important to understand that frozen chicken products often contain raw chicken, even though they may look pre-cooked on the outside. While additional measures have been put in place by food businesses to improve the safety of these products, consumers need to handle these products as they should other raw meat products. Cooking food at the right temperature and for the right amount of time will kill any Salmonella bacteria that may be in food. Therefore, we are urging consumers to follow cooking instructions for these products to protect themselves and their families.’

Food safety tips for frozen breaded chicken products:

  • Treat these products as raw chicken, ensuring they are steaming hot after cooking and surfaces they have touched are cleaned to avoid the spread of bacteria
  • Make sure the oven is up to temperature before cooking
  • Check the instructions on packaging and cook at the correct temperature and for the time stated
  • Wash your hands, utensils and clean surfaces after handling these products
  • If products require defrosting, follow the storage instructions on packaging and always defrost in the fridge

About this poll

The FSA and FSS commissioned an online survey via three waves of Ipsos MORI’s online omnibus of 5,599 adults (aged 16-75) living in the UK. Of these 3,740 had cooked or eaten coated frozen chicken products recently and went on to complete the full survey. The data was weighted to be representative of the UK adult population aged 16 – 75.

The full report is available in the research section of our website.

About the outbreak

FSA and FSS are continuing to work with Public Health England (PHE) and devolved public health authorities as well as our international food safety partners, via the United Nations’ World Health Organization, (WHO) and the Food and Agriculture Organization’s (FAO’s) International Food Safety Network (INFOSAN), to address the causes of the outbreak at source to prevent further cases of Salmonella Enteritidis.

Between January 2020 and May 2021 there have been 511 cases of Salmonellosis in the UK caused by two strains of Salmonella Enteritidis and linked to consumption of frozen, raw, breaded chicken products.

Authorities in Poland and UK retailers have taken action to reduce the risk from these products. Where non-compliant or unsafe food has been identified by the UK, action has been taken to protect consumers.

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Posted in food bourne outbreak, food contamination, Food Hazard, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, food recall, Food Safety, Food Safety Alert, foodborne outbreak, foodbourne outbreak, outbreak, Research, Salmonella, Salmonella in Chicken

Research – Prevalence of Listeria species and Listeria monocytogenes on Raw Produce Arriving at Frozen Food Manufacturing Facilities

Posted on June 21, 2021 by | Leave a comment

Journal of Food Protection

Ubiquity of Listeria monocytogenes in the environment impacts the food industry and presents concerns for frozen food facilities. This study determined the prevalence and numbers of Listeria species and L. monocytogenes on raw produce arriving at frozen food facilities. Raw produce was collected using multi-level blinding protocols to ensure anonymity of participants and avoid traceback. Five raw vegetables were selected: corn, carrots, green beans, peas, and spinach. Raw products were collected after arrival at the facilities but before any cleaning or other pre-processing steps that are typically performed inside the facility. The FDA BAM method for detection of Listeria spp. and L. monocytogenes was followed, with PCR screening followed by selective plating methods. Listeria numbers were estimated from positive samples using MPN methodology. A total of 290 samples were collected, with 96 and 17 samples positive for Listeria spp. (33.1%) and L. monocytogenes (5.9%), respectively. Enumeration data for the 96 Listeria spp. samples indicated 82 samples had greater than 100 MPN Listeria spp./g and 14 samples less than 100 MPN Listeria spp./g. The prevalence of Listeria spp. varied by commodity: spinach (66.7%), peas (50%), corn (32.2%), green beans (22.2%), and carrots (13%). L. monocytogenes prevalence was determined in corn (13.6%), peas (6.3%), and green beans (4.2%) arriving at processing facilities. Such data was previously unavailable to frozen vegetable processors and is valuable in implementing process control standards. The prevalence and pathogen concentration data from raw commodities found in this study can provide the industry information to conduct more accurate quantitative risk assessments and provide a baseline to model and target appropriate pathogen reduction steps during processing.

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Posted in Food Microbiology Research, Food Technology, Listeria, Listeria monocytogenes, MPN, Research, Technology

Research – Wet vs. dry inoculation methods have a significant effect of Listeria monocytogenes growth on many types of whole intact fresh produce

Posted on June 20, 2021 by | Leave a comment

Journal of Food Protection

L. monocytogenes causes relatively few outbreaks linked to whole fresh produce but triggers recalls each year in the US. There are limited data on the influence of wet vs. dry methods on pathogen growth on whole produce. A cocktail of five L. monocytogenes strains that included clinical, food, or environmental isolates associated with foodborne outbreaks and recalls was used. Cultures were combined to target a final wet inoculum concentration of 4-5 log CFU/mL. The dry inoculum was prepared by mixing wet inoculum with 100 g of sterile sand and drying for 24 h. Produce investigated belonged to major commodity families: Ericaceae (blackberry, raspberry, and blueberry), Rutaceae (lemon and mandarin orange), Roseaceae (sweet cherry), Solanaceae (tomato), Brassaceae (cauliflower and broccoli) and Apiaceae (carrot). Intact, whole inoculated fruit and vegetable commodities were incubated at 2, 12, 22 and 35±2°C. Commodities were sampled for up to 28 days, and the experiment was replicated 6 times. The average maximum growth increase was obtained by measuring the maximum absolute increase for each replicate within a specific commodity, temperature, and inoculation method. Data for each commodity, replicate and temperature was used to create primary growth or survival models, describing the lag phase and growth or shoulder and decline as a function of time. Use of a liquid inoculum (vs. dry inoculum) resulted in markedly increased L. monocytogenes growth rate and growth magnitude on whole produce surfaces. This difference was highly influenced by temperature with a greater effect seen with more commodities at higher temperatures (22 and 35°C), versus lower temperatures (2 and 12 °C). These findings need to be explored for other commodities and pathogens. The degree to which wet or dry inoculation techniques more realistically mimic contamination conditions throughout the supply chain (e.g., production, harvest, post-harvest, transportation, or retail) should be investigated.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Research

Norway – Handling of Salmonella in EU-EEA beef and pork (traded)

Posted on June 19, 2021 by | Leave a comment

Mattilsynet

In the winter and spring of 2021, several Salmonella finds were made in meat from Germany. On the basis of this, in 2021 the Norwegian Food Safety Authority will prioritize inspections of establishments that handle meat from EU / EEA countries (traded meat). The Norwegian Food Safety Authority will require the company to be able to verify that consignments of traded meat meet the conditions in the salmonella guarantee.

Companies in Norway must be able to verify that consignments of traded meat from EU / EEA countries meet the conditions in the Animal Hygiene Regulations (salmonella guarantee). This can be done by either referring to good enough historical documentation about the shipping business abroad, or increasing the sampling of traded meat in Norway.

Read more about Salmonella, what requirements the Norwegian Food Safety Authority places on companies that use processed meat, and how the Norwegian Food Safety Authority will follow this up, here: Handling of Salmonella in beef and pork from the EU / EEA (traded)

The Norwegian Food Safety Authority has, among other things, accelerated an already planned inspection of companies that import meat from EU / EEA countries.

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Posted in food contamination, Food Hazard, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, food recall, Food Safety, Food Safety Alert, Research, Salmonella

Research- Antimicrobial effects of plant extracts against Clostridium perfringens with respect to food-relevant influencing factors

Posted on June 19, 2021 by | Leave a comment

Journal of Food Protection

The application of plant extracts (PEs) could be a promising option to satisfy consumers’ demand for natural additives to inhibit growth of variable pathogenic bacteria. Thus, the aim of this study was to develop a standardized microdilution method to examine the antimicrobial effects of ten hydrophilic plant extracts against two strains of C. perfringens facing various food-relevant influencing factors. Due to the high opacity of PEs, resazurin was used as an indicator for bacterial growth instead of pellet formation. The highest value of the minimum inhibitory concentration (MIC) of the replications of each PE was defined as effective plant extract concentration (EPC), whereas the next concentration beneath the lowest MIC value was defined as the ineffective plant extract concentration (IEPC). The EPC of seven PEs: allspice, cardamom, cinnamon, clove, coriander, ginger and mace were between 0.625 – 10 g/kg, whereas extracts of caravey, nutmeg and thyme showed no antimicrobial activity up to the maximum concentration tested (10 g/kg) against C. perfringens in vitro. Two intrinsic factors, sodium chloride and sodium nitrite, displayed either synergistic/additive effects or no interaction with most PEs. By combination with PEs at its ineffective plant concentration (IEPC, 0.08 – 1.25 g/kg), MIC of NaCl and NaNO2 decreased from 25 – 50 g/kg to 6 – 25 g/kg and > 200 mg/kg to 0.2 – 100 mg/kg respectively. On the contrary, lipid (sun flower oil) at a low concentration inhibited the antimicrobial effects of all tested PEs. For extrinsic factors, only allspice, ginger and coriander could maintain their antimicrobial effects after being heated to 78 °C for 30 min. The synergistic effect between PEs and pH values (5.0 and 5.5) was also found for all PEs. The established screening method with resazurin and defining EPC and IEPC values allows the verification of antimicrobial effects of PEs under various food-relevant influencing factors in a fast and reproducible way.

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Posted in Antimicrobials, Clostridium, Clostridium perfringens, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Research

Research – Novel Sequence Types of Listeria monocytogenes of Different Origin Obtained in the Republic of Serbia

Posted on June 19, 2021 by | Leave a comment

MDPI

Listeria monocytogenes, the causative agent of listeriosis, is amongst the major food-borne pathogens in the world that affect mammal species, including humans. This microorganism has been associated with both sporadic episodes and large outbreaks of human listeriosis worldwide, with high mortality rates. In this study, the main sequence types (STs) and clonal complexes (CCs) were investigated in all of the 13 L. monocytogenes strains originating from different sources in the Republic of Serbia in 2004–2019 and that were available in the BIGSdb-Lm database. We found at least 13 STs belonging to the phylogenetic lineages I and II. These strains were represented by ST1/ST3/ST9 of CC1/CC3/CC9, which were common in the majority of the European countries and worldwide, as well as by eight novel STs (ST1232/ST1233/ST1234/ST1235/ST1238/ST1236/ST1237/ST1242) of CC19/CC155/CC5/CC21/CC3/CC315/CC37, and the rare ST32 (clonal complex ST32) and ST734 (CC1), reported in the Republic of Serbia, the EU, for the first time. Our study confirmed the association of CC1 with cases of neuroinfection and abortions among small ruminants, and of CC3 and CC9 with food products of animal origin. The strains isolated in 2019 carried alleles of the internalin genes (inlA/inlB/inlC/inlE) characteristic of the most virulent strains from the hypervirulent CC1. These findings demonstrated the genetic relatedness between L. monocytogenes strains isolated in the Republic of Serbia and worldwide. Our study adds further information about the diversity of the L. monocytogenes genotypes of small ruminants and food products, as the strain distribution in these sources in Serbia had not previously been evaluated.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Research

Research – “Aquaponics offers solutions to foodborne illness outbreaks”

Posted on June 18, 2021 by | Leave a comment

Horti Daily

Soilless growing offers a viable alternative to growing crops in a low-risk environment for many microbial sources. Aquaponics, which is often greenhouse-grown, is an innovative way of growing fish and plants in rural or urban settings. For years, commercial aquaponic farms have obtained food safety certifications from Global GAP, USDA Harmonized GAP, Primus GFS, and the SWF Food Safety Program, in addition to being certified USDA organic (Aquaponic Association, 2019) and sold commercially across North America.

In an aquaponic system, the healthy microbes actually serve as biological control agents against pathogenic bacteria making their survival minimal (Fox, 2012). While aquaponics produce is not immune to all pathogenic contamination, it is one of the safest agriculture methods against pathogenic risk.

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Posted in food bourne outbreak, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Technology, foodborne outbreak, foodbourne outbreak, microbial contamination, Microbiological Risk Assessment, Microbiology, outbreak, Research, Technology