By Dr Ashley Ward, Food Security Challenge Centre Facilitator, and Prof Nicola Holden, Professor in Food Safety, Scotland's Rural College (SRUC).

The theme for this year's annual WHO World Food Safety Day on Friday, 7th June, was ‘prepare for the unexpected’. A food safety incident occurs when an unexpected event compromises food safety, which can be from items in food that cause a threat to human health, such as chemical or microbial adulterants or physical items, as well as undeclared allergens. Events like World Food Safety Day increase awareness of the risks from food incidents and prepare us to handle the unexpected. 

In the UK, pathogenic micro-organisms are the most common cause of food incidents, as stated in the Food Standards Agency report for 2022-2023. Reducing the risk of foodborne illness from pathogenic microorganisms in the household is an effective and straightforward approach to being more prepared.   

Common causes of microbial foodborne diseases are norovirus, Salmonella, Listeria, Campylobacter and pathogenic Escherichia coli. These pathogens enter the food chain through improper hygiene, processing, storage or preparation, practices.  

The ‘prepare for the unexpected’ theme coincided with a UK-wide outbreak of Shiga toxin-producing E. coli (STEC). There are 256 reported cases (to date), with lettuce as the suspected source, nationally distributed in sandwiches. The variant of STEC has been identified (STEC O145) and is responsible for previous outbreaks, including another UK outbreak at Christmastime 2023/2024 from contaminated cheese made with unpasteurised milk. This serotype, a group of intimately related microorganisms distinguished by a common set of antigens, causes a high level of hospitalisations of cases. Consumer advice on the outbreak was provided from UKHSA. SCAF member  Nicola Holden (who sits on SCAF advisory steering group) provided further information to the Science Media Centre on this matter, which generated UK-wide media interest in the story on the risks of this STEC pathogen.   

STEC is a food- and contact-borne pathogenic variant of E. coli. Although most E. coli are entirely harmless, often carried in human intestinal tracts, STEC can cause serious diseases from diarrhoea to haemolytic uremic syndrome (HUS), a kidney disease. Young children are most susceptible to STEC infection, which can be fatal.  

The STEC group continues to evolve, creating a challenge to understand which can cause disease and identify them in diagnostic settings. On top of that, not all are pathogenic, adding to the challenge of working out which has the potential to cause disease. Thus, the WHO call for ‘preparing for the unexpected’ rings especially true as we grapple with this group of pathogens.   

About the authors: 

Prof Nicola Holden is a Professor in Food Safety at Scotland's Rural College (SRUC), whose work is driven by the major challenges facing our food production and public health. She is a molecular bacteriologist by training, working on microbial interactions in crop production. Her research focus is on food safety, looking at biological threats in the food chain and implications from emerging technology such as vertical farms. Nicola also holds a policy fellowship with Scottish Government, working with the Chief Science Advisor on epidemics and infections within the one Health remit. She is a member of the SCAF Advisory Steering group. 

Dr Ashley Ward is the Food Security Challenge Centre Facilitator at SRUC with experience in molecular research, health, and disease. 

10 tips for good food hygiene: 

 1. Wash hands thoroughly and frequently with warm, soapy water thoroughly and frequently, always after using the bathroom and before preparing food.  
 

2.  Use warm, soapy water and bleach-based cleaning products to keep food storage, preparation areas, and utensils clean.  

 
3.  Avoid cross-contamination between raw and cooked foods.  
 

4.  Know the difference between use-by and best-before dates: ‘Use-by’ is about safety; don’t eat it after this date. ‘Best before’ is about quality; usually fine to eat after this date, but the quality may not be at its best.  
 

5. Ensure that chilled products are kept chilled (check storage guidance on packaging) and discard them when they haven’t been.  
 

6. Thaw frozen foods in a refrigerated environment to prevent the growth of microorganisms.  
 

7.  Discard (or thoroughly clean where appropriate) foods that have contacted the floor. No ‘5-second rule’, sorry!  
 

8.  Thoroughly cook meats according to the instructions on the packaging. Check out the Food Standards Scotland guide to safe barbecuing this summer.  
 

9.  Wash fruits and vegetables before eating or peeling.  
 

10.  Don’t prepare food for others when suffering from a gastrointestinal illness. 

First published: 25 June 2024

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