What is a food sample?
To check that food and drink intended for human consumption is safe, food samples are purchased anonymously or taken with the owners consent by an authorised officer. These samples will be analysed by the Public Health England, Food, Water and Environmental Microbiology Laboratory Birmingham, Good Hope Hospital in Birmingham or the Public Analyst to see whether they comply with the Guidelines for Assessing the Microbiological Safety of Ready-to-Eat Foods Placed on the Market.
Why are food samples taken?
We sample to:
- identify potential problems with specific types of food or types of food businesses as part of national or regional studies
- investigate food poisoning outbreaks and food contamination incidents
- investigate complaints
- assess food suspected of being sub-standard
- reassure the public about food safety
- deliver a more effective food inspection service.
When will a food sample be taken?
Food samples are usually taken in the following situations:
- Food Standards Agency co-ordinated sampling programmes
- PHE (Public Health England) co-ordinated sampling programmes
- Shropshire and Staffordshire Food Sampling Group surveys
- home or originating authority responsibilities
- as part of routine food hygiene inspections to aid assessment of food safety management
- investigation of complaints.
What do the results mean?
When food samples are examined the results are interpreted as one of the four grades of microbiological quality and these are detailed below:
The term applied to food which is of good microbiological quality and therefore the numbers of bacteria found were relatively low or not detected in the food.
The term applied to foods that reflect a borderline limit of microbiological quality and therefore the numbers of bacteria detected were higher than expected. A review of food handling procedures is necessary to ensure that safe food is produced.
The term applied to foods with relatively high numbers of bacteria and indicates a problem with food hygiene and handling procedures. A review of working procedures must be conducted and Food Safety Officers may take additional food samples together with further inspection of the premises to determine the possible cause of the contamination.
The food sample taken from your premises will have been tested for some, or all, of the following bacteria:
- The Aerobic Colony Count (ACC)
Is the total number of bacteria found in food. This examination is usually carried out on most foods; the exception being those foods that would naturally contain high levels of harmless bacteria e.g. salamis and milk products. A high ACC may indicate the product has been kept too long or that it has been left unrefrigerated.
Refrigeration of food slows down bacterial growth, but does not destroy bacteria.
- Escherichia coli (E.coli)
Is a bacterium, which is found in the gut of man and animals. It may be transmitted through faecal contamination at slaughter or through poor personal hygiene of food handlers. Its presence in cooked foods is indicative of poor personal hygiene, e.g. not washing hands after going to the toilet. There is a strain of E.coli (O157) which can cause serious illness and this bacterium is associated with raw or undercooked meat, e.g. burgers.
When cooking, the centre temperature of meats should therefore reach at least 70°C for two minutes, or an equivalent temperature/time combination, or until the juices run clear. Always ensure cooked foods are separated from raw.
The family includes bacteria that naturally inhabit the gut of man and animals but some are widespread in the environment. Enterobacteriaceae are useful indicators of hygiene and of post processing contamination of processed foods (e.g. from dirty machinery). Some of these bacteria are found in the environment and are therefore commonly found in salad/vegetable products or in cooked foods coming into contact with raw foods.
It is essential therefore, that salads are thoroughly cleaned and that cooked and raw foods are kept separate.
- Staphylococcus aureus
Is a bacterium that can produce a toxin that can in turn cause food poisoning. This bacterium is found in the nose and mouth of humans and in uncovered wounds, cuts, spots, boils etc. The presence of these bacteria in food is usually due to poor personal hygiene.
It is essential that hands are washed before handling food and that touching the nose and/or mouth is avoided during food handling.
- Clostridium perfringens
Is a bacterium that is found in the gut of animals and humans and in the environment.
Cooking at a high temperature for sufficient time will reduce the presence of this bacteria It is also important to prevent cross-contamination during preparation from raw to ready-to-eat foods.
- Bacillus species and specifically Bacillus cereus
These are food poisoning bacteria. Bacillus is widely distributed in the environment and therefore found on grains, beans, pulses etc. This bacterium is usually associated with rice dishes where large volumes of food are produced in advance and may be cooled slowly over several hours.
It is essential that such foods are cooked thoroughly, and if not being served immediately they must be cooled rapidly and then stored in the fridge. Refrigeration slows down growth of bacteria.
- Listeria species, especially Listeria monocytogenes
Are found in the environment and usually associated with salads, pâtés and soft cheese. Their presence in cooked foods can be an indicator of insufficient cooking or contact with raw foods. As they can grow well at refrigeration temperatures, it is important not to keep ready to eat food for too long.
It is essential that foods are cooked thoroughly and covered during storage, and that all food equipment and surfaces are cleaned thoroughly.
- Salmonella species
Are food poisoning bacteria which can be found in the intestines of animals, humans and in polluted waters. Salmonella may be present in food due to insufficient cooking of contaminated foods, or from cross-contamination from raw food e.g. raw poultry to cooked foods (which includes the use of raw eggs in uncooked dishes) or due to poor personal hygiene.
Thorough cooking and correct handling will prevent Salmonella contamination.
These bacteria are known to cause food poisoning. This bacterium is found in the gut of some animals. Its presence in foods may be due to insufficient heat treatment or cooking (e.g. unpasteurised milk, uncooked centre of rolled meat joints) or contamination by pets and other domestic animals.
Food must be cooked thoroughly and once cooked not allowed to come into contact with raw foods or pets.
Follow these simple rules to help you to control the quality and safety of your food:
- identify all steps in your activities which are critical to food safety
- put adequate safety controls in place
- adequately train all staff in food hygiene
- wash hands thoroughly before handling food, and again between handling raw and cooked foods and after visiting the toilet
- clean all equipment, utensils and preparation surfaces thoroughly
- keep cooked and raw foods separate during preparation and storage
- wash salad, vegetables and fruit thoroughly if they are to be eaten raw
- use food within its use-by date and promptly use foods you have already prepared
- keep food covered
- never use raw shell eggs in food which is not going to be cooked e.g. mayonnaise, tiramisu
- keep animals out of food preparation areas
- use a thermometer to monitor temperatures and disinfect the temperature probe before (and after) each time that it is used
- cook food thoroughly (centre temperature more than 70°C for 2 minutes) and serve. If hot-holding keep above 63°C
- re-heat food to at least 75°C
- ensure any food requiring refrigeration is kept below 8°C and not left at room temperature for long periods
- when preparing food in advance, ensure it is cooked thoroughly, cooled rapidly and stored in the fridge
- avoid using left-overs.
Last updated: 11.04am on Sunday 29 October 2017