Category Archives: Food Microbiology Research

Scotland – Precautionary advice on cooking processed chicken products following link to UK cases of Salmonella


27 October 2020

Article: 54/4306

Food Standards Scotland (FSS) and Public Health Scotland (PHS) are reminding consumers to take care when handling and cooking chicken products at home. This advice comes as both organisations are involved in a multi-agency investigation into a suspected rise in cases of Salmonella linked to processed chicken products, such as nuggets, goujons, dippers, poppers and kievs.

Since January 2020, there have been 390 cases of salmonellosis across the UK, caused by two strains of Salmonella enteritidis linked to frozen, raw and breaded chicken products. Of these cases, 32 were in Scotland.

FSS advise that people do not need to make changes to the food they purchase, but they should always follow good hygiene practices to help reduce the risk of food poisoning. These practices include:

  • always carefully checking the advice on food packaging and following the cooking instructions provided
  • following instructions to thaw or defrost before cooking, if required
  • consuming or freezing food by its use-by date
  • washing hands after touching raw chicken products, and before handling ready-to-eat food
  • avoiding cross-contamination by cleaning any surface, plate or utensil that has been in contact with raw meat

Source: FSS, 16 October 2020

UK – FSA welcomes the outcome of the Hospital Food Review


The Independent Review of NHS Hospital Food was announced by Health and Social Care Secretary Matt Hancock following a listeriosis outbreak in 2019.

The final report (Opens in a new window), published today, includes a number of recommendations to improve food safety, based largely on evidence provided by the FSA. These recommendations include having dedicated food safety specialists in each trust, hospitals implementing robust food safety management systems, and a compulsory function to report concerns across the entire hospital food chain. Crucially, NHS Trusts must also recognise that they are food business operators and responsible for ensuring that the food they provide is safe.

Research – New file of the Map of dangers on the ciguatera


In the Hazard Map database we have added in the group of chemical hazards, such as marine toxins, the ciguatera.

Fish poisoning called ciguatera or ciguatera fish poisoning (CFP) occurs because they have ingested a large amount of ciguatoxin-producing algae: these are benthic dinoflagellates of the genus Gambierdiscus spp .

Cytokines (CTXs) accumulate in the fish that ingest them directly (rockfish) or in their predators, where this accumulation reaches higher levels.

Research – The effects of environmental factors on the prevalence and diversity of bacteriophages lytic against the top six non‐O157 Shiga toxin‐producing Escherichia coli on an organic farm

Wiley Online

Bacteriophages (or phages) specific to Shiga toxin‐producing Escherichia coli (STEC) strains are frequently isolated from animal‐associated environments primarily because ruminant animals are the natural reservoir of STEC. However, little is known about these phages in produce‐growing environments. The objective of this study was to determine the effects of environmental factors on the prevalence of the phages lytic against O157 and the top six non‐O157 STEC on an organic farm. A total of 370 samples were collected from an organic farm, containing animal‐active and produce‐growing areas, for 1 year. A bacterial cocktail, including nonpathogenic and pathogenic Ecoli strains, was used for phage isolation. Meanwhile, culture methods and PCR were used to isolate STEC strains. Weather information was also collected for each sampling trip. Twenty‐eight samples contained phages lytic against STEC (or STEC‐infecting phages), of which 26 were collected from the animal‐active area. Moreover, the winter season had a higher phage prevalence than other seasons, likely due to high rain precipitation. The phages belonging to the Myoviridae family and those lytic against STEC O103 were the most prevalent. One Ecoli O103:H2 was isolated from a water sample where no STEC O103‐infecting phages were found. Additionally, no STEC O103 was present in the samples containing STEC O103‐infecting phages. The findings indicate that animal is the primary factor contributing to the prevalence of the STEC‐infecting phages in the surrounding environment of the organic farm, and the presence of these phages contributes to a negative correlation with their STEC hosts.

Research – Survival of Salmonella on red meat in response to dry heat

Journal of Food Protection

Red meat is associated with Salmonella outbreaks resulting in negative impacts for the processing industry. Little work has been reported on the use of dry heat as opposed to moist heat against Salmonella on red meat. We determined the effect of drying at 25°C and dry heat at 70°C with ~10% relative humidity (RH) for 1 h against eleven Salmonella strains of multiple serovars on beef, lamb, goat, and rubber as an inert surface. Each strain at ~108 cfu/ml was inoculated (100ul) onto ±1g (1cm2) of each surface and allowed to attach for 15 min in a microcentrifuge tube. Samples were then exposed to 70°C and 25°C with ~10% RH in a heating block. Surviving Salmonella numbers on surfaces were enumerated on a thin layer medium. If numbers were below the limit of detection (LOD), (2.01 log cfu/cm2), Salmonella cells were enriched before plating to determine the presence of viable cells. Water loss (%) from meat after at 25°C and 70°C was determined. Whole genomes of Salmonella were interrogated to identify the presence/absence of stress response genes (n=30) related to dry heat which may contribute to the survival of Salmonella. The survival of Salmonella at 25°C was significantly higher across all surfaces (~6.09–7.91 log cfu/cm2) as compared to 70°C (~3.66–6.33 log cfu/cm2). On rubber, numbers of Salmonella were <LOD at 70°C. Water loss at 70°C (~17.72–19.89%) was significantly higher as compared to 25°C (~2.98–4.11%). Salmonella was not detected on rubber while survival occurred on all red meat at 70°C, suggesting its protective effect against the effect of heat. All Salmonella strains carried 30 stress response genes which likely contributed to its survival. A multi-antibiotic resistant S. Typhimurium 2470 exhibited an increase in heat resistance at 70°C on beef and lamb as compared to other strains. Our work shows that dry heat at 70°C for 1 h against Salmonella on red meat is not a practical approach for effectively reducing or eliminating them from red meat.

Norway – The inspection program for shellfish 2019


Shells along the Norwegian coast have low concentrations of E. coli, heavy metals and other undesirable substances. It shows the results from the annual monitoring of bacteria and environmental toxins in mussels from production areas and mussel samples taken in connection with the Norwegian Food Safety Authority’s mussel warning.

What did we investigate? Mussels, scallops, flat oysters, Pacific oysters, cow mussels, O-mussels, carpet mussels, king snails and Drøbakkråkebolle.
Period: 2019
What were we looking for? E. coli, Salmonella and the environmental toxins cadmium, mercury, dioxins and dioxin-like PCBs, as well as polyaromatic hydrocarbons.
What did we find? About 90 percent of all submitted mussels were below the limit of E. coli and there were no detections of Salmonella. A total of 453 E. coli samples and 26 salmonella samples were analyzed.

Mussels: All examined mussels were below the limits for environmental toxins.

Scallops: No excesses of environmental toxins in muscle and gonads. Flat oysters: Cadmium was detected above the limit value in two samples.

O-shells and king snails: The heavy metal cadmium was, as in previous years, proven well above the limit value. The majority of heavy metals, such as cadmium and lead, have previously been localized to the kidneys. The Norwegian Food Safety Authority therefore recommends that the kidneys be removed before consumption, so that edible parts fall well below the limit values.

Research – UK hit hardest by outbreak linked to Brazil nuts; no cases in U.S. yet

Food Safety News

More than 120 people are part of a multi-country Salmonella outbreak linked to Brazil nuts.

Since August 2019, the outbreak, caused by Salmonella Typhimurium and Salmonella Anatum, has affected three European Union countries, the United Kingdom and Canada. The United States was one of more than 30 countries that received Brazil nuts from Bolivia contaminated with Salmonella.

In total, 123 cases of Salmonella Typhimurium have been reported, of which 105 were in the UK, 14 in France, three in Luxembourg and one each in the Netherlands and Canada. One Salmonella Anatum patient was recorded in the UK.

A case-control study in the UK and patient interviews in the UK, France and Luxembourg indicated Brazil nuts and nut bars as likely vehicles of infections. Two batches of Brazil nuts from Bolivia tested positive for Salmonella Typhimurium and Salmonella Anatum matching the outbreak strains.

Research – Food Fraud With Nasty Results – Norovirus

Food Safety Tech

Norovirus Food Safety kswfoodworld

Global food supply chains are complex and therefore quite vulnerable to errors or fraudulent activity. A company in Chile repackaged and falsely labeled cheap raspberries from China, reselling them as top-level organic Chilean raspberries in Canada. These raspberries were linked to a norovirus outbreak in Canada, sickening hundreds of people. A whistleblower complaint helped to uncover this fraudulent scheme that posed a significant risk to human health.

Research – Assessment of spoilage potential posed by Alicyclobacillus spp. in plant-based dairy beverages mixed with fruit juices during storage

Journal of Food Protection

The scope of the present study was to assess the spoilage potential of different Alicyclobacillus spp. in commercial pasteurized (ambient-stable) plant-based dairy beverages mixed with fruit juices at different inoculation levels and storage temperatures. Different products (Coconut and Berry‒CB; Almond, Mango, and Passionfruit‒AMP; Oat, Strawberry, and Banana‒OSB) were inoculated with 10 or 2×103 spores/mL of either Alicyclobacillus acidoterrestris or A. fastidiosus or A. acidocaldarius strain composites, while non‒inoculated samples served as controls. Samples inoculated with A. acidoterrestris and A. fastidiosus were stored at 30°C and 45°C, while in case of A. acidocaldarius storage took place at 50°C for 240 days. Gas composition, Alicyclobacillus spp. populations, total viable counts, pH, aw, color, and guaiacol off-taste were monitored. CB and AMP supported growth of A. acidoterrestris and A. fastidiosus, reaching populations of 4.0‒5.0 log CFU/mL. In OSB, populations of the latter species remained close to the initial inoculation levels during storage at 30°C, while at 45°C, the populations declined <1 CFU/mL. A. acidocaldarius growth was supported only in CB samples, reaching ca. 3.0 log CFU/mL at 50°C, regardless of initial inoculum size. Total color change was increased during storage, however the instrumentally recorded color changes were not macroscopically visible. Spoilage in terms of guaiacol off-taste, was identified only in CB and AMP samples inoculated with A. acidoterrestris after 60 days at 30°C and 45°C. Considering that these products are becoming increasingly popular and the scarcity of existing literature related to their spoilage by Alicyclobacillus spp., the contribution of the findings and data of present study are critical for assessing the significance of Alicyclobacillus spp. as a potential spoilage hazard in these products and thus, to assist in the design and implementation of effective mitigation strategies by the beverage industry.

USA – Outbreak Investigation of Salmonella Enteritidis: Peaches (August 2020)


The FDA, along with CDC, Canadian, state and local partners, has been investigating a multistate outbreak of Salmonella Enteritidis infections linked to peaches packed or supplied by Prima Wawona or Wawona Packing Company.

The multistate outbreak of Salmonella Enteritidis infections linked to peaches from Prima Wawona that were sold in several regions of the United States and Canada, investigated by the FDA, along with CDC and Canadian, state, and local partners, is over. As of October 15, 2020, CDC reported a total of 101 cases across 17 states. This outbreak resulted in recalls of bagged and bulk, or loose, peaches packed or distributed by Prima Wawona. FDA also worked to publicly disclose international distribution of recalled product from Prima Wawona in an effort to facilitate the swift removal of all potentially affected product from the international market. More information about international distribution of the recalled product can be found in the previously published table below. FDA’s traceback investigation, which included 18 cases across eight states, identified multiple distributors, packing facilities, and orchards that supplied peaches during the time period of interest. Investigators from FDA, the California Department of Public Health (CDPH) and the California Department of Food and Agriculture (CDFA) visited Wawona packing facilities and/or orchards that likely supplied peaches to Prima Wawona during the timeframe of interest. FDA’s traceback investigation is ongoing; however, the cause and source of the outbreak has not yet been determined.

Thus far, in an effort to investigate several possible pathways of contamination, FDA has completed over 570 product and environmental sample analyses from multiple facility locations and/or peach orchards, including environmental swabs, peaches and peach tree leaf samples. At this time, sample collection and analysis is underway related to additional peach orchards. A genetic match to the outbreak strain has yet to be identified in any of the samples collected, although a different serotype of Salmonella was detected in one sample collected and analyzed during the investigation. No peaches linked to the positive sample ever reached the marketplace. Although the outbreak is being declared over, FDA will continue its investigation and will communicate any findings that could assist future prevention efforts.

Available recall information is included below.


On August 22, 2020, Prima Wawona recalled bagged and bulk, or loose, peaches that they supplied to retailers nationwide.

The recalled products are now well beyond expiration and likely no longer on the market or in consumers’ homes. However, consumers who may have frozen the recalled bagged peaches packed or supplied by Prima Wawona from June 1, 2020 to August 19, 2020 or the recalled loose/bulk peaches packed or supplied by Prima Wawona from June 1, 2020 to August 3, 2020 should throw them away.