Trading Standards Institute Advice

Food borne illness and contamination: Staphlyococcus aureus

This leaflet is for all food businesses, including those involved in catering, food production, food preparation, retail premises, restaurants, pubs, cafes, and fast-food shops.

What is Staphylococcus aureus?
Staphylococcus is a common organism and can be found on the skin or in the ears, nose and throat of healthy people, where it lives harmlessly. There are large numbers of Staphylococcus aureus in boils, sores, cuts and acne and most importantly up to 10% of the body's Staphylococcus aureus are found on our hands.

Once contaminated, if food is prepared too early and left in warm conditions such as at room temperature, bacteria cells will start to multiply and the bacteria will leave a poison (toxin) in the food. Staphylococcus aureus will multiply in temperatures between 7° and 48°C (being most active at 35°C).

These bacteria will grow with or without the presence of oxygen, are salt tolerant and can grow in salty foods like ham. Although the bacteria will be destroyed at normal cooking temperatures, the toxin produced is heat resistant and may not be affected and therefore food poisoning may occur.

How does food get contaminated?
In food premises and catering environments, the main reason food gets contaminated by Staphylococcus aureus is the poor personal hygiene of the food handler, such as:

  • coughing and sneezing, touching the nose, mouth, and spots
  • scratching the head, brushing back hair with a hand
  • leaving cuts open and uncovered while preparing food

Poultry and other animals can also carry the bacteria, which can be found in cows' udders, and with high levels being found in unpasteurised milk from cows or goats suffering from mastitis. It may even come from the milk of healthy animals.

Which foods are most at risk of contamination or infection?
Foods commonly linked with Staphylococcus aureus food poisoning may have been touched by hand, especially ready-to-eat foods that have been handled while warm and left standing for a while before being eaten. For example, a cold buffet that hasn't been put into a fridge may be at risk of food poisoning unless you have put the right controls and monitoring in place.

Foods at risk include:

  • milk, cheese and egg products
  • desserts and custards
  • ham, other cooked meats and poultry
  • prawns

What are the effects or symptoms after eating contaminated food?
Once eaten, the toxin can act quickly and there may be symptoms within 30 minutes.

Normally, a victim of food poisoning may experience abdominal pain, vomiting and, occasionally, diarrhoea one to seven hours after eating contaminated food.

These symptoms may last from between six hours up to three days depending on the amount of toxin in the food and how the victim responds.

The toxins do not pass easily from one person to another so the illness is not contagious.

The best treatment for people with food poisoning is to rest and drink plenty of fluids.

High-risk groups, such as the very young and the elderly, are more likely to have a serious food-poisoning illness that will need medical attention.

How do I control or prevent Staphylococcus aureus?
FITNESS TO WORK
All people handling food must report any illness or condition they have that may increase their risk of contaminating food. They must also make sure that they have a bath or shower before they start work to reduce bacteria on their body and hair.

You should consider whether a food handler is fit to work if they are coughing or sneezing, or if they have a runny nose, spots, boils or septic cuts.

If a food handler has these or any other open skin infections you should not let them handle food unless you can put controls in place. Handkerchiefs must not be used in production or storage areas.

If a food handler uses a tissue, they should dispose of it straightaway and then wash their hands before handling any food.

PLASTERS
Waterproof plasters must be used to cover cuts, sores or any broken skin. The plasters should be blue so they are easy to see should they come off or fall into food.

If the area is too big to be covered by a plaster, you should use a finger stall or glove instead.

Sometimes waterproof plasters do not stick to the skin very well. In these circumstances the use of vinyl gloves is a useful addition to protecting the food.

HAND WASHING
Anyone handling food should wash their hands thoroughly before and after all food-preparation tasks. Gloves may be worn if appropriate - but they must be changed regularly or they may become a source of cross-contamination.

Food handlers should always wash their hands, whether they wear gloves or not. Rings and bangles can stop people washing their hands properly and can also transfer bacteria to food.

You need to provide:

  • enough wash basins exclusively for hand washing
  • wash basins that are in a convenient place to use
  • wash basins that are close to toilets, near the kitchen entrance and that have hot and cold running water - and
  • liquid soap dispensers and paper towels at each wash basin

FOOD PREPARATION AND TEMPERATURE CONTROL: 

  • use only pasteurised milk and milk products
  • don't prepare food, especially high-risk food, too early without considering how you are going to keep it safe before you serve it
  • keep the food either hot or cold
  • you should cook food so that the middle of it reaches a minimum of 75°C and then keep it hot (above 63°C) or cool it quickly, within one and a half hours
  • you should then put food in the fridge and keep it below 5°C
  • you should not keep hot food at a temperature of under 63°C or cold food above 5°C for any longer than possible

KEEP HANDLING TO A MINIMUM
Plan the production of your food, and keep handling to a minimum. Use clean utensils.

TRAINING
You should let staff know that they must keep to high hygiene standards. Introduce the importance of personal hygiene, a clean workplace and hygienic food preparation techniques as part of staff training and promote these with posters and signs. Supervisors and managers should encourage their staff, lead by example and check the workplace to make sure that they are keeping to hygiene standards.

More information
You will find further guidance in our other leaflets on this website. Information can also be found on the Food Standards Agency website.

Alternatively, contact your local environmental health service for advice.

Please note
This leaflet is not an authoritative interpretation of the law and is intended only for guidance.

© 2017 itsa Ltd.