Category Archives: Decontamination Microbial

UK – How to safely host a street party

FSA

Official Jubilee Flags Queen Elizabeth Platinum 2022 Official Merchandise

The Platinum Jubilee Weekend takes place from 2 June to 5 June with lots of Big Lunches also taking place during this time. The bank holiday weekend will be a big celebration with many people attending and organising parties or gatherings in their local communities.

Whether you are attending a community party or hosting one of your own, it is important to be aware of food safety and hygiene. Below are some practical tips and advice on best practice so that everyone can trust the food they’re eating.

Selling food at a street party

You do not need a food hygiene training certificate to make and sell food for charity events. However, you need to make sure that you handle food safely.


Handling party food

Warm weather and outdoor cooking are the perfect conditions for bacteria to grow and there are risks when preparing and serving chilled food in these conditions.

Following the 4Cs of food hygiene will help you prepare, make and store food safely. You can do this by:

  • cleaning effectively removes the bacteria on hands, equipment and surfaces. This helps to stop harmful bacteria and viruses from spreading onto food.
  • chilling your food below 8 degrees will stop or significantly slow the growth of bacteria. This temperature must be maintained and foods that need to be chilled like sandwich fillings should not be left out of the fridge for more than four hours.
  • cooking food correctly by following the guidance on time and temperature
  • avoiding cross-contamination which might lead to bacteria passing from raw foods to ready-to-eat foods via things like re-usable shopping bags, knives and chopping boards.
  • good personal hygiene is also essential when you’re preparing food. This will help ensure that bacteria you may have come into contact with isn’t passed to your friends, family and neighbours in their food.

Best practice

Here are some practical tips to help keep food you prepare and eat safe during your Jubilee celebrations:

  • wash your hands regularly with soap and water before food preparation and consumption
  • always wash fresh fruit and vegetables
  • keep raw and ready-to-eat foods apart
  • do not use food past its use-by date
  • always read any cooking instructions and make sure food is properly cooked before you serve it – it needs to be piping hot
  • ensure that food preparation areas are cleaned and sanitised before and after use and ensure equipment is washed in hot soapy water
  • plan ahead to keep your food cool until you’re ready to eat. Any foods which you would usually keep in the fridge at home also need to be kept cool on your picnic. This includes; any food with a use-by-date, cooked dishes, salads and dairy products
  • place these foods in a cool box or cool bag with ice or frozen gel packs. Distribute these throughout the box or bag, not all at the bottom. You can also use frozen drinks to help keep your cool box cold. Store cold food below 5 degrees to prevent bacteria from growing.

If food isn’t handled properly people are at risk of food poisoning from:

  • campylobacter – spreads through the cross-contamination from raw chicken
  • listeria – is most commonly associated with chilled, ready-to-eat foods like cured meats, pre-prepared sandwiches and salads
  • salmonella – is most often found in undercooked poultry, raw meat, eggs or unpasteurised milk
  • E.coli – it is often found on raw and undercooked meats

Read our Providing food at community and charity events for specific advice about making and serving cakes at community events.

Our picnic advice contains more tips on how to keep food cold and safe.

If you are hosting a BBQ then please read our BBQ food safety information.

Bear in mind that on hot days you need to be extra vigilant. 

UK – Research – A survey of Salmonella, Escherichia coli (E. coli) and antimicrobial resistance in frozen, part-cooked, breaded or battered poultry products on retail sale in the United Kingdom

FSA

A survey of Salmonella, Escherichia coli (E. coli) and antimicrobial resistance in frozen, part-cooked, breaded or battered poultry products on retail sale in the United Kingdom

In this study we estimated how frequently Salmonella spp. were present in frozen, breaded or battered chicken products, intended to be cooked before consumption, on retail sale in the UK between April and July 2021.

Frozen, breaded, ready-to-cook chicken products have been implicated in outbreaks of salmonellosis. Some of these outbreaks can be large. For example, one outbreak of Salmonella Enteritidis involved 193 people in nine countries between 2018 and 2020, of which 122 cases were in the UK. These ready-to-cook products have a browned, cooked external appearance, which may be perceived as ready-to-eat, leading to mishandling or undercooking by consumers. Continuing concerns about these products led FSA to initiate a short-term (four month), cross-sectional surveillance study undertaken in 2021 to determine the prevalence of Salmonella spp., Escherichia coli and antimicrobial resistance (AMR) in frozen, breaded or battered chicken products on retail sale in the UK.

This study sought to obtain data on AMR levels in Salmonella and E. coli in these products, in line with a number of other FSA instigated studies of the incidence and nature of AMR in the UK food chain, for example, the systematic review (2016).

Between the beginning of April and the end of July 2021, 310 samples of frozen, breaded or battered chicken products containing either raw or partly cooked chicken, were collected using representative sampling of retailers in England, Wales, Scotland and Northern Ireland based on market share data. Samples included domestically produced and imported chicken products and were tested for E. coli (including extended-spectrum beta-lactamase (ESBL)-producing, colistin-resistant and carbapenem-resistant E. coli) and Salmonella spp. One isolate of each bacterial type from each contaminated sample was randomly selected for additional AMR testing to determine the minimum inhibitory concentration (MIC) for a range of antimicrobials. More detailed analysis based on Whole Genome Sequencing (WGS) data was used to further characterise Salmonella spp. isolates and allow the identification of potential links with human isolates.

Salmonella spp. were detected in 5 (1.6%) of the 310 samples and identified as Salmonella Infantis (in three samples) and S. Java (in two samples). One of the S. Infantis isolates fell into the same genetic cluster as S. Infantis isolates from three recent human cases of infection; the second fell into another cluster containing two recent cases of infection. Countries of origin recorded on the packaging of the five Salmonella contaminated samples were Hungary (n=1), Ireland (n=2) and the UK (n=2). One S. Infantis isolate was multi-drug resistant (i.e. resistant to three different classes of antimicrobials), while the other Salmonella isolates were each resistant to at least one of the classes of antimicrobials tested. E. coli was detected in 113 samples (36.4%), with counts ranging from ❤ to >1100 MPN (Most Probable Number)/g. Almost half of the E. coli isolates (44.5%) were susceptible to all antimicrobials tested. Multi-drug resistance was detected in 20.0% of E. coli isolates. E. coli isolates demonstrating the ESBL (but not AmpC) phenotype were detected in 15 of the 310 samples (4.8%) and the AmpC phenotype alone was detected in two of the 310 samples (0.6%) of chicken samples. Polymerase Chain Reaction (PCR) testing showed that five of the 15 (33.3%) ESBL-producing E. coli carried blaCTX-M genes (CTX-M-1, CTX-M-55 or CTX-M-15), which confer resistance to third generation cephalosporin antimicrobials. One E. coli isolate demonstrated resistance to colistin and was found to possess the mcr-1 gene.

The five Salmonella-positive samples recovered from this study, and 20 similar Salmonella-positive samples from a previous UKHSA (2020/2021) study (which had been stored frozen), were subjected to the cooking procedures described on the sample product packaging for fan assisted ovens. No Salmonella were detected in any of these 25 samples after cooking.

The current survey provides evidence of the presence of Salmonella in frozen, breaded and battered chicken products in the UK food chain, although at a considerably lower incidence than reported in an earlier (2020/2021) study carried out by PHE/UKHSA as part of an outbreak investigation where Salmonella prevalence was found to be 8.8%.

The current survey also provides data on the prevalence of specified AMR bacteria found in the tested chicken products on retail sale in the UK. It will contribute to monitoring trends in AMR prevalence over time within the UK, support comparisons with data from other countries, and provide a baseline against which to monitor the impact of future interventions. While AMR activity was observed in some of the E. coli and Salmonella spp. examined in this study, the risk of acquiring AMR bacteria from consumption of these processed chicken products is low if the products are cooked thoroughly and handled hygienically.

Research – Seafood safety and food‐borne zoonoses from fish

EFSA

Parasitic nematodes of the genus Anisakis are the causative agent of anisakiosis, an important fish‐borne zoonosis. Humans are infected through consumption of raw or undercooked fish, contaminated with the parasite. Infection can result in both gastrointestinal and allergic symptoms. There are few reports of anisakiosis in Portugal, but evidence of Anisakis allergy exists, indicating that exposure is occurring in the population. The European Food Risk Assessment Fellowship Programme (EU‐FORA) work programme, entitled: ‘Food safety of fish and zoonoses: fish consumption and microbiological risk assessment and perception, from fisherman to final consumers in Portugal’ was hosted by the Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), in Porto, Portugal. It aimed to gather information on risk perception and attitudes in the Portuguese population to contamination of fish with Anisakis spp. and on their knowledge of methods to prevent infection. In addition, it aimed to examine the risk of anisakiosis in the Portuguese population.

Research – Evaluation of Potential for Butyl and Heptyl Para-Hydroxybenzoate Enhancement of Thermal Inactivation of Cronobacter sakazakii during Rehydration of Powdered Infant Powdered Infant Formula and Non-Fat Dry Milk.

Journal of Food Protection

Prior studies have demonstrated that parabens enhanced the thermal inactivation of foodborne pathogens including Cronobacter sakazakii , Salmonella enterica serotype Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes in model systems. However, there have been few studies looking at this phenomenon in actual food systems. The current study evaluated the potential enhancement of thermal inactivation of C. sakazakii by butyl para-hydroxybenzoate (BPB) in powdered infant formula (PIF) and non-fat dry milk (NFDM) before and after rehydration. When PIF was rehydrated with water at designated temperatures (65 – 80 ºC) in baby bottles, BPB did not enhance thermal inactivation. Rehydrated NFDM and lactose solutions with BPB were inoculated and heated at 58 ºC, BPB enhancement of thermal inactivation was negatively associated with NFDM levels in a dose-dependent manner, whereas presence of lactose retained thermal enhancement regardless of its concentration, suggesting an interaction between proteins and BPB. Fluorescence tests further indicated an interaction between BPB and the proteins in PIF and NFDM. Inoculated dry NFDM with and without BPB stored at 24 ºC and 55 ºC for 14 days did not substantially enhance inactivation in the dry state. This study suggests that BPB is not likely to enhance mild thermal inactivation treatments in foods that have appreciable amounts of protein.

Research – Comparison of Selected Phenotypic Features of Persistent and Sporadic Strains of Listeria monocytogenes Sampled from Fish Processing Plants

MDPI

(1) Background: The main source of transmission of Listeria monocytogenes is contaminated food, e.g., fish and meat products and raw fruit and vegetables. The bacteria can remain for 13 years on machines in food processing plants, including fish plants.

(2) Methods: A total of 720 swabs were collected from a salmon filleting line. The research material consisted of 62 (8.6%) L. monocytogenes isolates. Pulsed Field Gel Electrophoresis (PFGE) allowed detecting a pool of persistent strains. All persistent strains (n = 6) and a parallel group of strains collected sporadically (n = 6) were characterized by their ability to invade HT-29 cells, biofilm formation ability, and minimum bactericidal concentrations (MBC) of selected disinfectants.

(3) Results: Among the obtained isolates, 38 genetically different strains were found, including 6 (15.8%) persistent strains. The serogroup 1/2a-3a represented 28 strains (73.7%), including the persistent ones. There were no significant differences in invasiveness between the persistent and sporadic strains. The persistent strains tolerated higher concentrations of the tested disinfectants, except for iodine-based compounds. The persistent strains initiated the biofilm formation process faster and formed it more intensively.

(4) Conclusions: The presence of persistent strains in the food processing environment is a great challenge for producers to ensure consumer safety. This study attempts to elucidate the phenotypic characteristics of persistent L. monocytogenes strains. View Full-Text

Research – A risk assessment model for Salmonella spp. in swine carcasses

EFSA

Salmonellosis is one of the most important food‐borne outbreaks that occurs in the EU/EEA. From the first production stages at slaughter, meat is susceptible to spoilage and can be a substrate for the pathogenic microorganisms growth. Among the pathogens, the presence of Salmonella is mainly due to mishandling during the evisceration stage. For the year 2019, according to the collected data from MSs, on the 17.9% of all food‐borne outbursts, the presence Salmonella was confirmed. Pork meat is considered as one of the four most commonly reported foods in cases of salmonellosis. For the training purposes of this project, Salmonella isolation and identification along with RA for carcass contamination, was performed. Pig carcasses were sampled using the non‐destructive technique. The sampling took place post dressing and before the stage of chilling. For the Salmonella detection, a three phases process was performed (pre‐enrichment, enrichment, isolation). A total of 757 samples were collected, 19 were found to be positive for Salmonella. The most common was found to be Salmonella Derby, which was identified eight times. The main objective of the project was to determine the prevalence of Salmonella spp. in swine carcasses. Moreover, certain parameters were evaluated in terms of their influence on the prevalence of Salmonella. A stochastic simulation model was developed in Microsoft Office Excel 2019 by using the add‐in @Risk v.8.1. The prevalence was estimated to be 2.6%. For the pigs sampled, the average value of the distance from farm to slaughterhouse was 200.92 km. Additionally, the average weight of the carcasses was 127.97 kg. The prevalence of Salmonella between the samples that came from farms with a distance above the average, was higher by 1.7 units, while the prevalence for the samples with weight above the average was higher by 0.2 units. According to the stochastic model, it is specified that the prevalence is higher with greater distance, and there is an 8.1% probability the prevalence will exceed the legislation’s – hygiene criteria. In addition, the prevalence of Salmonella was shown to increase, as well in the case of samples from weightier animals, but to a lesser extent.

Norway Research – Outbreaks stable but illnesses down in 2021 

Food Safety News

The number of foodborne outbreaks in Norway has remained steady but fewer people were sick in 2021 compared to the year before.

A total of 25 foodborne outbreaks were announced this past year, which is on a par with 23 in 2020 but down compared to 46 in 2019 and 52 in 2018.

Overall, 327 people fell sick in the 25 outbreaks in 2021 with a range of three to 30 patients per outbreak. The 23 outbreaks in 2020 affected 495 people.

Data comes from a report that gives an overview of outbreaks and related illnesses reported to the Norwegian Institute of Public Health (FHI) in 2021.

Research – A Review of Essential Oils as Antimicrobials in Foods with Special Emphasis on Fresh Produce

Journal of Food Protection

Consumer safety concerns over established fresh produce washing methods, combined with demand for organic and clean label food, has led to the exploration of novel methods of produce sanitization. Essential oils (EOs), extracted from commonly found plants have potential as clean label sanitizers, as they are naturally derived and act as antimicrobials as well as antioxidants. In this review, the antimicrobial abilities of EOs are explored in the following categories: individually and in-combination, as emulsions, combined with existing chemical and physical preservation methods, incorporated into films and coatings, and in vapor phase. We examine combining EOs with one another, with EO components, with surfactants, or with other preservatives or preservation methods to increase sanitizing efficacy.  Components of major EOs are also identified, chemical mechanisms are discussed, and potential for antibacterial resistance and effect on organoleptic properties is examined. Studies reveal that EOs can serve as equivalent or better sanitizing agents than chlorine; nevertheless, concentrations must be kept low to avoid adverse sensory effects. For this reason, it is crucial that future studies address the maximum permissible EO concentrations, which do not negatively affect sensory properties.  This review should be beneficial to food scientists or industry personnel interested in sanitization and preservation of foods, including fresh produce with EOs.

Research – The Response and Survival Mechanisms of Staphylococcus aureus under High Salinity Stress in Salted Foods

MDPI

Staphylococcus aureus (S. aureus) has a strong tolerance to high salt stress. It is a major reason as to why the contamination of S. aureus in salted food cannot be eradicated. To elucidate its response and survival mechanisms, changes in the morphology, biofilm formation, virulence, transcriptome, and metabolome of S. aureus were investigated. IsaA positively regulates and participates in the formation of biofilm. Virulence was downregulated to reduce the depletion of nonessential cellular functions. Inositol phosphate metabolism was downregulated to reduce the conversion of functional molecules. The MtsABC transport system was downregulated to reduce ion transport and signaling. Aminoacyl-tRNA biosynthesis was upregulated to improve cellular homeostasis. The betaine biosynthesis pathway was upregulated to protect the active structure of proteins and nucleic acids. Within a 10% NaCl concentration, the L-proline content was upregulated to increase osmotic stability. In addition, 20 hub genes were identified through an interaction analysis. The findings provide theoretical support for the prevention and control of salt-tolerant bacteria in salted foods. View Full-Text

USA – BEAM Dashboard

CDC

The BEAM (Bacteria, Enterics, Amoeba, and Mycotics) Dashboard is an interactive tool to access and visualize data from the System for Enteric Disease Response, Investigation, and Coordination (SEDRIC). The BEAM Dashboard provides timely data on pathogen trends and serotype details to inform work to prevent illnesses from food and animal contact. Currently, the dashboard focuses on data for Salmonella bacteria, but it will eventually include additional pathogens, antimicrobial resistance data, and epidemiologic data from outbreak investigations.

Frequently Asked Questions (FAQ)

For additional questions, please contact simso@cdc.gov.