Category Archives: Food Microbiology Research

Research – Annual report on the food safety situation in Catalonia, 2020


Based on the available data collected in the 2020 Report, we can conclude that the situation in this matter remains, in general terms, stable. However, the COVID-19 pandemic has generated significant deviations in some parameters such as, for example, food poisoning outbreaks that have deviated widely from the usual data of the historical series of the last twenty years with a drop of more than 50% compared to previous years.

Click to access Memoria-anual-seguretat-alimentaria_2020-Final1.docx.pdf

USA – Holiday Reminder: Raw Dough Can Contain Dangerous Pathogens

Food Poisoning Bulletin

It’s time for the annual holiday reminder: raw dough can contain dangerous pathogens. While most people know that eating raw eggs is risky, fewer know that uncooked flour is also a potential hazard.

The FDA has been warning consumers about the potential dangers of raw eggs for decades. Eggs can carry Salmonella bacteria not only on the shell, but inside the egg itself. Hens can carry the pathogen in their ovaries, so the eggs are then contaminated from the inside out. Always handle raw eggs as if they are contaminated. Cook them thoroughly, and avoid recipes that use raw eggs. Eggs that are pasteurized are safe to eat raw, as long as you follow expiration dates.

There have been outbreaks linked to raw, or uncooked flour, in the past few years. Flour is a raw agricultural product and can be contaminated just like cantaloupe and romaine lettuce.

So when you are baking this holiday season, there are some things to remember. Follow package directions on baking mixes and four containers. Keep flour and eggs away from foods that are eaten uncooked. Refrigerate cookie and pastry dough if you aren’t going to be baking immediately.

Never eat or taste raw dough or cake batter unless it is made with pasteurized eggs and commercial heat-treated flour. Do not make play dough out of raw flour. Don’t use cake mixes to make milkshakes. While there are instructions for heat-treating your flour at home, the FDA doesn’t recommend it, since these treatments may not kill all pathogens. There are several brands of commercial heat-treated flour you can buy. Don’t use raw cookie dough in ice cream.

Sweden provides detail on outbreaks in 2021

Food Safety News

Sweden has noted an increase in foodborne outbreaks and illnesses in 2021 but levels were still below pre-COVID-19 pandemic figures.

The number of outbreaks reported to the Swedish Food Agency (Livsmedelsverket) in 2020 and 2021 was affected by measures taken during the pandemic.

There were 251 reports of suspected or confirmed food poisoning outbreaks with 1,467 illnesses. Both the number of reports and the number of cases increased compared to 160 outbreaks and 1,314 cases in 2020 but are still lower than the historical average.

When several Coronavirus-related restrictions were lifted in the autumn of 2021, the number of cases increased. Sixteen major outbreaks occurred during this season.

Eleven people have been hospitalized in seven outbreaks and one person died during a Campylobacter epidemic which infected eight people.

Slovenia – Salmonella outbreak in Slovenia, Steak tartare linked as possible source

Outbreak News Today

kswfoodworld salmonella

The Administration for Safe Food, Veterinary Medicine and Plant Protection (UVHVVR) together with the National Institute of Public Health (NIJZ) is investigating the increased number of reported cases of salmonella infections in Slovenia, which are being handled by the regional units of the NIJZ Ravne na Koroškem, Murska Sobota, Celje and Ljubljana. On the basis of the information received from the epidemiological service of the NIJZ, the UVHVVR started inquiries and inspections.

The epidemiological investigation showed that there were mostly unrelated cases, but the probability of consuming the same food stood out.

Research -Application of a novel phage ZPAH7 for controlling multidrug-resistant Aeromonas hydrophila on lettuce and reducing biofilms

Science Direct


Aeromonas hydrophila is an important pathogenic bacterium that causes foodborne illness worldwide. In this study, virulent phages from the sediment of a fish farm were propagated and isolated on a multidrug-resistant strain of A. hydrophila, ZYAH75. One phage, designated as ZPAH7, featured a unique turbid halo around a clear plaque on the bacterial lawn (indicative of potential depolymerase activity), and was selected for further analysis. ZPAH7 was classified as podophage by morphological and genomic methods. Further comparisons of genome nucleotide similarity, ratios of homologous proteins and phylogenetic relatedness among the terminase large subunit and major capsid proteins of similar phage deposited in GENBANK, led us to propose a new genus, ZPAH7virus, in the Autographivirinae subfamily of Podoviridae. ZPAH7 had an adsorption rate of 79% in 5 min, an eclipse period of 15 min, a latent period of 25 min, and a burst size of 148 ± 9 PFU/cell. Antimicrobial application experiments showed that ZPAH7 lead to significantly reduction on A. hydrophila on lettuce. Additionally, ZPAH7 was able to inhibit biofilm formation, as well as degrade and kill bacteria in established biofilms. Furthermore, lytic activity of ZPAH7 remained stable across a wide range of temperatures and pH measurements. These results suggest ZPAH7 could be used as a potential biological control agent against A. hydrophila on food and/or biofilms on food contact surfaces.

Research – Dynamic Changes of Bacterial Communities and Microbial Association Networks in Ready-to-Eat Chicken Meat during Storage


Ready-to-eat (RTE) chicken is a popular food in China, but its lack of food safety due to bacterial contamination remains a concern, and the dynamic changes of microbial association networks during storage are not fully understood. This study investigated the impact of storage time and temperature on bacterial compositions and microbial association networks in RTE chicken using 16S rDNA high-throughput sequencing. The results show that the predominant phyla present in all samples were Proteobacteria and Firmicutes, and the most abundant genera were WeissellaPseudomonas and Proteus. Increased storage time and temperature decreased the richness and diversity of the microorganisms of the bacterial communities. Higher storage temperatures impacted the bacterial community composition more significantly. Microbial interaction analyses showed 22 positive and 6 negative interactions at 4 °C, 30 positive and 12 negative interactions at 8 °C and 44 positive and 45 negative interactions at 22 °C, indicating an increase in the complexity of interaction networks with an increase in the storage temperature. Enterobacter dominated the interactions during storage at 4 and 22 °C, and Pseudomonas did so at 22 °C. Moreover, interactions between pathogenic and/or spoilage bacteria, such as those between Pseudomonas fragi and Weissella viridescensEnterobacter unclassified and Proteus unclassified, or those between Enterobacteriaceae unclassified and W.viridescens, were observed. This study provides insight into the process involved in RTE meat spoilage and can aid in improving the quality and safety of RTE meat products to reduce outbreaks of foodborne illness. View Full-Text

Research – Contamination of eggs by Salmonella Enteritidis in experimentally infected laying hens of four commercial genetic lines in conventional cages and enriched colony housing

Science Direct


Human illness caused by the consumption of eggs contaminated with Salmonella Enteritidis is a continuing international public health concern. This pathogen is deposited inside the edible contents of eggs as a consequence of its ability to colonize reproductive tissues in infected hens. Conditions in the housing environment can influence the persistence and transmission of avian Salmonella infections, but the food safety ramifications of different poultry management systems are not entirely clear. The present study assessed the deposition of S. Enteritidis inside eggs laid by groups of experimentally infected laying hens of 4 commercial genetic lines (designated as white egg lines W1 and W2 and brown egg lines B1 and B2). Groups of hens from each line were housed at 555 cm2 of floor space per bird in both conventional cages and colony units enriched with access to perches and nesting areas. All hens were orally inoculated with 5.75 × 107 cfu of a 2-strain S. Enteritidis mixture, and the internal contents of eggs laid 5 to 24 D post-inoculation were cultured to detect the pathogen. No significant differences in egg contamination frequencies were found between the 2 housing systems for any of the hen lines. Contaminated eggs were laid between 7 and 21 D post-inoculation at an overall frequency of 2.47%, ranging from 0.25 to 4.38% for the 4 hen lines. The frequency of S. Enteritidis recovery from egg samples was significantly (P < 0.05) lower for line B2 than for any of the other lines, and the egg contamination frequency for line W1 was significantly greater than for line W2. The overall incidence of contamination among white eggs (3.38%) was significantly higher than among brown eggs (1.56%). These results demonstrate that S. Enteritidis deposition inside eggs can vary between genetic lines of infected laying hens, but housing these hens in 2 different systems did not affect the production of contaminated eggs.

Research – Bacterial microbiota profile in gills of modified atmosphere-packaged oysters stored at 4 °C

Science Direct

french oysters


As filter-feeding bivalves, oysters can accumulate microorganisms into their gills, causing spoilage and potential safety issues. This study aims to investigate the changes in the gill microbiota of oysters packed under air and modified atmospheres (MAs, 50% CO2: 50% N2, 70% CO2: 30% O2, and 50% CO2: 50% O2) during storage at 4 °C. The diversity of bacterial microbiota in oyster gills was profiled through polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis on the 16S rRNA gene V3 region to describe the variation during the entire storage period. The DGGE profile revealed high bacterial diversity in the air- and MA-packaged oyster gills, and the spoilage bacterial microbiota varied in the MA-packaged oyster gills. Results indicated that CO2:O2 (70%:30%) was suitable for oyster MA packaging and that high bacterial loads in oyster gills need to be considered during storage. In addition, Lactobacillus and Lactococcus species were found to grow dominantly in fresh oyster gills under MA packaging, which supports the potential application of MA packaging for oyster storage.

Research – Salmonella enterica Outbreaks Linked to the Consumption of Tahini and Tahini-Based Products


kswfoodworld Salmonella

Salmonella is a leading cause of bacterial foodborne illness in the world. Although typically associated with foods of animal origin, low-moisture foods, such as tahini, are quickly gaining recognition as an important vehicle of Salmonella exposure. This review offers the Canadian perspective on the issue of Salmonella in tahini and tahini-based products. A summary of several recent food product recalls and foodborne outbreaks related to the presence of Salmonella in tahini and tahini-based products such as halva are presented. The properties of the food vehicles, their production practices, and potential routes of contamination are discussed. Particular focus is placed on the ecology of Salmonella in the tahini production continuum, including its survival characteristics and response to intervention technologies. View Full-Text

Quebec – Notice not to consume bagels prepared and sold by Côte St-Luc Bagel inc.


QUEBEC CITY , Nov. 24, 2022 /CNW Telbec/ – The Ministry of Agriculture, Fisheries and Food (MAPAQ), in collaboration with the Food Inspection Division of the City of Montreal and the company Côte St-Luc Bagel inc., located at 5757 Caldwell Avenue, in Montreal, advises the public not to consume any bagel sold by the latter, because the products have not been prepared and packaged in such a way as to ensure their safety.

The products that are the subject of this warning were offered for sale until November 23, 2022, only at the establishment designated above. The products were sold and packaged by the attendant at the request of customers.

The operator is voluntarily recalling the products in question. It has agreed with MAPAQ to issue this warning as a precautionary measure. Also, people who have any of these products in their possession are advised not to consume it. They must return it to the establishment where they bought it or throw it away. Even if the affected products show no signs of tampering or suspicious odors, their consumption may represent a health risk. No case of illness associated with the consumption of these foods has been reported to MAPAQ to date.