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Skip to 0 minutes and 1 secondFood hazards can be broadly grouped into four different categories - physical, chemical, allergenic, and biological. We're now going to consider each category of hazard in more detail. Physical hazards - when a foreign body enters our food, this is known as a physical hazard. Physicals hazards would often be large enough to be visible to the naked eye upon close inspection of the food product. Sources and types of physical hazards include raw ingredients - for example, bones, stalks, or dirt, food packaging - for example, string, plastic, or card, buildings and equipment - for example, wood splinters, flaking paint or screws, food handlers - such as jewellery, hair, blue plasters, or pests - for example, dead bodies or droppings.

Skip to 0 minutes and 59 secondsForeign bodies such as glass or a stone could cut a customer's mouth, break teeth or cause choking. Even if no injury occurs, the presence of a physical hazard will be objectionable to the customer and is likely lead to customer complaints. Food companies will put in place internal checks for physical hazards as part of HACCP monitoring.

Skip to 1 minute and 23 secondsChemical hazards - we can all identify chemicals in our lives and most people would name examples such as detergents or pesticides, which are man-made. Unwanted chemicals both natural and man-made can enter foodstuffs during growth of plants or animals for example, veterinary drugs, fertilisers, pesticides, and environmental contaminants such as lead or dioxins - processing or food preparation for example oil, cleaning chemicals, or insecticides - transport as a result of spillage or leakage - sale for example cleaning chemicals, insecticides, and leaking of such things as plasticizers from packaging - or they may be produced during food processing for example acrylamide or degradation products - or they may be added during food processing for example dyes, or colorings.

Skip to 2 minutes and 20 secondsAllergens - some hazards added to food can cause allergies. Their addition may not affect every one, but it's important to recognise their potential to cause illness in a proportion of the population. The big eight foods responsible for 90% of allergic reactions to food in the UK are milk/dairy, eggs, peanuts, which can be ground nuts or monkey nuts, nuts more generally including Brazil nuts, hazelnuts nuts, almonds, and walnuts, fish due to histamine, shellfish including mussels, crab, and shrimps, soya, wheat, and other potential allergens include celery, mustard, sesame, and sulphites.

Skip to 3 minutes and 12 secondsBiological hazards - biological hazards are living organisms or products of living organisms present in food or feed. Certain living organisms may be visible to the naked eye for example some parasites, but more often they will be microscopic, i.e. requiring a microscope to be visible, or invisible in the case of toxins.

Skip to 3 minutes and 37 secondsMicrobiological hazards include viruses, fungi, bacteria, and parasites.

Skip to 3 minutes and 44 secondsNumerous parasites can be transmitted by food including many protozoa and helminths.

Skip to 3 minutes and 50 secondsThe most common foodborne parasites are protozoa such as cryptosporidium species, giardia species, cyclospora species, and toxoplasma gondii, round worm such as trichinella species and anasakis species, and tapeworm such as taenia species. Parasites are transmitted in foods such as undercooked fish, crabs, and molluscs, undercooked meat, raw aquatic plants such as water cress, and raw vegetables that have been contaminated by human or animal faeces. Marine biotoxins are produced by algae and they may be present in fish and shellfish. Microorganisms such as bacteria, fungi, and viruses are the main causes of food safety issues. Bacteria are present everywhere. They are ubiquitous. But only certain types are harmful.

Skip to 4 minutes and 48 secondsThe main foodborne bacterial pathogens to cause health problems for humans would be salmonella species, campylobacter jejuni, enteropathogenic escherichia

Skip to 4 minutes and 59 secondscoli such as 0157:H7, listeria monocytogenes, staphylococcus aureus, clostridium botulinum, clostridium perfringens and bacillus cereus. Mycotoxins for example aflatoxins are toxins produced by fungi growing in food or feed under improper storage conditions. Viruses can be foodborne, but food items tend to become contaminated when they are handled by an infected person. Examples would be hepatitis A, and norovirus.

Skip to 5 minutes and 36 secondsSo how do bacteria make people ill? They upset the digestive system, causing vomiting and/or diarrhoea, which are the body's defence mechanisms. Some bacteria need to be consumed in food in high numbers to cause illness for example salmonella.

Skip to 5 minutes and 52 secondsIn the case of others for example E coli 0157:H7, the presence of just a few bacteria may be sufficient to cause problems. Some need to multiply inside the gut to exert their effects. Some produce toxins either in food before consumption, when they're known as exotoxins, or inside the body when they're known as endotoxins. The young, the elderly, and the immunocompromised are particularly vulnerable to foodborne illness. There are many sources of hazards in food including ingredients, air, water, soil, food handlers - in other words, people - packaging materials, animals, rodents, insects, and food contact surfaces, including machinery, and food processing preparation environment.

Skip to 6 minutes and 46 secondsEssentially anything that food may come in contact with during its primary production, harvesting, further processing, storage, or transport, may act as a source of contamination.

Skip to 7 minutes and 0 secondsWith such a huge potential for hazards of various kinds to enter the food chain, it's imperative that processes are developed to detect, notify, and prevent contaminated food reaching the consumer. In this section, we will learn about an information system within the European Union, known as the Rapid Alert System for Food and Feed or RASFF, which collects and disseminates information on food hazards as and when they are detected by member states.

Food hazards

Food hazards are anything in or on food which has the potential to cause harm to the consumer.

There is a range of hazards which fall into 4 categories:

  • Chemical
  • Microbiological
  • Physical
  • Allergens

In this video we will look at each class of food hazard in a little more detail.

  • Can you provide examples of recent or high profile incidents relating to food hazards identified and/or reported in your country or region?

Please share links to these in the comments sections below.

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This video is from the free online course:

Tackling Global Food Safety

Queen's University Belfast