Foodborne Illness

A key priority for Food Standards Scotland is to protect consumers in Scotland from the risks of foodborne illness.  Most foodborne illness in Scotland is caused through the consumption of food which has become contaminated with pathogenic microorganisms such as bacteria and viruses.

Regulations exist to ensure food businesses take appropriate steps to control food safety risks before products are placed on the market. To support food safety management, we apply a ‘farm-to-fork’ approach; to try to ensure contamination is minimised as much as possible during the production and processing of food before it reaches the kitchen. We’re also promoting good food hygiene practices through the development of guidance for Scottish food businesses and caterers; and advice to help consumers understand the risks and keep themselves and their families safe.  All of our work is supported by research to ensure all of our strategies and interventions are effectively targeted and evidence based.

For more on keeping food safe for business, see our guidance and regulations pages.

For more on keeping food safe in your home, see our consumer food safety pages.

Main causes of foodborne illness in Scotland

In Scotland it is estimated there are 43,000 cases of foodborne illness with 5,800 GP presentations and 500 hospital admissions. We’re working closely with the Food Standards Agency and Scottish partners such as Health Protection Scotland to target the pathogens which cause the highest number of cases of foodborne illness.

Health Protection Scotland (HPS) is responsible for undertaking surveillance of infectious intestinal disease (IID) caused by the key pathogens of interest. This surveillance records the total number of cases of IID including those which have been transmitted through the foodchain as well as other sources such as contaminated water or the environment. Trends for the number of cases of each of Food Standards Scotland’s key foodborne disease targets are shown in the graph below. Further details on surveillance of IID are published on the HPS website and summarised in our joint annual report on IID in Scotland.

Campylobacter

For information, see our Campylobacter page. You might also like our Campylobacter factsheet for caterers and other small businesses.

Verotoxigenic E. coli

Verotoxigenic E. coli is known as VTEC. This includes E. coli O157.

VTEC is an important public health challenge in Scotland, as it continues to cause outbreaks of infection, severe illness and, in some cases, death, particularly among the very young. Clinical aspects of infection VTEC can be asymptomatic, or cause a spectrum of illness ranging from mild diarrhoea, bloody diarrhoea and haemorrhagic colitis. Haemolytic uraemic syndrome (HUS), a consequence of VTEC which can lead to kidney failure is more likely in those aged under 16 or over 60 years.

With over 200 cases of E. coli O157 each year, Scotland has consistently recorded the highest rates of infection per 100,000 head of population in the UK since the late 1980s. Non-domestic animals, particularly ruminants, are the main reservoir of the organism, which rarely causes disease in livestock. Infection occurs when humans ingest organisms originating from animal faeces, most directly by contact with grazing animals or their environments, or contaminated food or water.

Two large outbreaks of E. coli O157 infection (Wishaw 1997 and South Wales 2005) resulted from poor cross-contamination controls by Butchers, which lead to the spread of the pathogen to ready to eat food from contaminated raw meat. The FSA has developed guidance on the steps for food businesses to take in order to control cross-contamination between raw foods that are a potential source of E. coli O157 and ready-to-eat foods. You can read more on cross-contamination guidance on food.gov.uk.

In response to recommendations made by the report of the Public Inquiry into the 2005 South Wales outbreak, the FSA in Scotland hosted an international E. coli research workshop in November 2011 that identified the research needed to improve understanding of E. coli O157 supershedding by cattle and potential on-farm intervention strategies for reducing colonisation and transmission.

In November 2013, Scottish Government’s VTEC/E. coli O157 Action Plan for Scotland was published. This sets out 86 recommendations designed to tackle VTEC/E. coli O157 infection in Scotland. FSS is a member of the multi-agency Action Group that considered ways to disrupt the transmission routes for VTEC from source to humans and has sole or joint responsibility for 23 of the recommendations. These cover VTEC controls at primary production, monitoring of contamination at abattoirs, implementation of the cross-contamination guidance and robust enforcement of controls at butchers and caterers across Scotland, communication of food hygiene messages to consumers, and research to improve our understanding of the pathogen and risks in the foodchain.

Listeria monocytogenes

The public health importance of Listeria monocytogenes as a gastro-intestinal pathogen arises not from the number of reported cases, which is relatively low (10-20 cases annually in Scotland) compared with many other pathogens, but rather due to the severity of infection, high mortality, and the fact that it is foodborne. Infection with Listeria monocytogenes causes influenza like illness, septicaemia or a meningo-encephalitis. Pregnant women, newborn infants, the elderly and immunocompromised are most at risk.

Due to the long incubation period for Listeria monocytogenes (up to 90 days) it is difficult to determine the key sources of infection from traditional epidemiological methods. However, there have been outbreaks in hospitals that have been attributed to sandwiches. Also, sampling of foodstuffs undertaken by local authorities have shown listeria to be present in smoked salmon, cheeses and cooked sliced meats.

Our work is aimed at reducing the risks of Listeria monocytogenes in the production, storage and handling of chilled ready to eat foods which are most commonly associated with human illness. A key priority is to identify effective measures for controlling the organism in the production of ready to eat foods and developing tools to assist food businesses and high-risk food sectors.

We have produced an online tool to help smoked fish producers manage the risk of contamination of their product by Listeria monocytogenes, which is often found in the production areas of manufacturers of smoked fish. This initiative aims to help producers of these foods to follow best practice so they can reduce the risk of contamination of their products.

It is also a priority for us to ensure information about risk and avoidance is communicated effectively so listeriosis can be prevented among high-risk groups. We have been working with FSA to provide guidance for staff with responsibility for providing food in hospitals, nursing homes, etc. to allow them to identify and manage the critical control points specific to controlling Listeria in the food supply chain, with the ultimate aim of reducing the risk of vulnerable groups contracting listeriosis in these settings.

Salmonella

Salmonella is the second most commonly reported cause of bacterial infectious intestinal disease in Scotland after Campylobacter. Common symptoms include diarrhoea, stomach cramps, nausea, fever and occasionally vomiting. These symptoms usually last 4-7 days and clear up without treatment.

Salmonella can cause illness through a number of routes including contaminated food, environmental exposure, or transmission from infected animals.

During the late 1990s, when vaccination against Salmonella Enteritidis was introduced in the poultry industry, there was a 37% decrease in the number of cases of Salmonella in Scotland, and in following years the numbers have continued to decline annually.

EU Regulation requires Member States to take effective measures to detect and control Salmonellas of public health significance in specified animal species at all relevant stages of production. National Control Programmes have been established in the UK to reduce the prevalence of Salmonella in poultry and pigs at primary production level. They cover farm animal species which present a potential risk of transmitting Salmonella and other zoonotic agents to humans. This work is led by Defra and devolved Agriculture Departments in the UK, although the FSA actively participates in these activities.

Salmonella remains an important pathogen that still causes a large number of cases and is responsible for a large number of outbreaks each year. Therefore FSA continues to monitor the incidence of Salmonella cases and outbreaks to ensure that a downward trend in case numbers continues, and is prepared to take further action if the situation worsens.

Foodborne viruses

The virus which is most commonly linked to food is norovirus, which is also known as ‘winter vomiting disease’, although it can occur at any time of year. Infection usually causes a mild, short lived illness (which usually lasts 12-60 hours) characterised by sudden onset nausea followed by projectile vomiting and diarrhoea. Dehydration may occur and hospital treatment is sometimes necessary, particularly for those at the extremes of age.

Norovirus is highly infectious, and person-to-person spread accounts for a high proportion of cases, with outbreaks common in semi-closed settings including carehomes, schools, nurseries, hotels and cruise ships. However norovirus infection can also occur through contact with contaminated environments; eating food which has been grown in or treated with contaminated water (e.g. shellfish or fresh produce); or by infected food handlers. The true contribution made by food to the rates of norovirus infection in Scotland is currently unknown, and FSA is funding a large programme of research to improve understanding in this area.

You can also see our current and published projects on our Research pages.

Other causes of foodborne illness

 

Marine biotoxins

Biotoxins can be produced by certain species of naturally occurring marine phytoplankton, and detected levels are higher in summer months. Food Standards Scotland has a monitoring programme in place that regularly monitors shellfish harvesting waters and closes areas where biotoxins are detected at levels which exceed the legal limit. The four main groups of marine biotoxins which are monitored in Scotland can cause the following illnesses:

Amnesic Shellfish Poisoning (ASP)

Caused by the neurotoxin domoic acid (DA) and its variants. ASP is characterized by gastrointestinal disorders (vomiting, diarrhea, abdominal pain) with higher doses leading to more serious neurological problems (confusion, short-term memory loss, disorientation, seizure, coma), particularly in elderly patients.

Diarrhetic Shellfish Poisoning (DSP)

Caused by a group of lipophilic toxins including okadaic acid, and dinophysistoxins (collectively known as DSTs). DSP generally causes mild gastrointestinal disorders which can last from 2-3 days including nausea, vomiting, diarrhoea, and abdominal pain, which can be accompanied by chills, headache, and fever.

Azaspiracid shellfish poisoning (AZP)

Caused by the lipophillic toxin azaspiracid and several derivatives (AZAs). To date, more than 30 AZA analogs have been identified, with three analogs routinely monitored in shellfish. Symptoms are predominantly gastrointestinal disturbances resembling those of diarrhetic shellfish poisoning and include nausea, vomiting, stomach cramps, and diarrhea. Illness is self-limiting, with symptoms lasting 2 or 3 days.

Paralytic Shellfish Poisoning (PSP)

Caused by a group of water soluble neurotoxins that are collectively referred to as saxitoxins or paralytic shellfish toxins (PSTs). PSP causes neurologic symptoms ranging from a tingling of the lips, mouth, and tongue to numbness, weakness, dizziness, and headache; and in severe cases can lead to respiratory paralysis and death.

Further information on marine biotoxins, our shellfish monitoring programme, and guidance on shellfish safety can be found on our Shellfish pages.

Chemical and Radiological contaminants

Foodborne illness can also occur following the consumption of food or drink that has become contaminated with either naturally occurring or man-made chemicals. Food Standards Scotland works with FSA and other government agencies to assess the potential food safety risks arising from chemical contaminants and take appropriate action to protect public health.

Radioactivity exists naturally in the environment and is also created by human activity such as nuclear power stations and military operations. Inevitably some of this enters the food chain and levels are strictly monitored and controlled to protect public health.

For more information, see our Contaminants page

For more information on our Foodborne Illness programme, contact us at foodbornedisease@fss.scot.

Related Publications/Resources