Food-borne Illness

FOOD SAFETY AND HYGIENE IN CATERING -Part 2 

Food-borne Illness

Introduction

Here, we will look at the main food-borne illnesses and how they may affect us.

The main food-borne illnesses can be split into 3 categories:

1. Microorganisms- Bacteria, viruses, mould.
2. Chemicals- Cleaning agents, additives, pesticides (inc. fungicides, rodenticides, insecticides), cross-contamination of allergens, metallic elements.
3. Natural Poisons- Certain foods contain naturally-occurring toxins, e.g. some fungi, certain pulses, tubers, leaves and flowers, some fish and shellfish.

Food-borne illness may occur when food has been contaminated, and can result in food poisoning or a food-borne disease. Contaminated food may not always be obvious to spot - contaminated food can sometimes look, smell, feel and taste just like it should - which is why it is so important to exercise good food safety and hygiene measures in order to minimise the risk of contamination.

The time delay between eating contaminated food and showing symptoms of illness is known as the incubation period or onset time.

The onset time of one contaminant can vary greatly from another. For example, a bacterial cause such as E-Coli 0157 can have an onset time of 2-3 days, whereas the bacteria Staphylococcus aureus can present symptoms in just 1-2 hours. 

Fungal toxins can present themselves in a matter of minutes or after many hours, and can be fatal if untreated. 

Chemical contamination (from a cleaning agent, for example) could manifest itself within 30 minutes. The onset time is also dictated by the person who has become infected - a fit and healthy 25 year old woman may take 3 days to show signs of E-Coli infection, but an elderly woman or young child may present symptoms within a day.

When struck down with food poisoning most people will blame the last thing they ate… but because of the onset time of some contaminants, this may not be the case.

Vulnerable Groups

For the most part, a food-borne illness will cause little more than mild discomfort and inconvenience. But for some sectors of society the risk of harm is much greater, and can even result in serious illness or death.

These include:

• The Very Young
• The Elderly
• Pregnant Women
• People Recovering from Illness
• People with a Weakened Immune System
• Hospital Patients

This is why good food safety and hygiene practices are so important. When we serve food to a customer we simply cannot know their current state of health. By following safe practices we are able to minimise the chance of anybody becoming ill from the food we serve.

Once a person is infected with a food-poisoning bacteria they become a carrier. This means that the bacteria is present within their systems and they have the potential to pass that bacteria on to others. 

Sometimes a person can be carrying food-poisoning bacteria without ever having shown signs of illness. Other people may have recovered from food-poisoning and appear to be perfectly well, but the bacteria remains in their systems; these are known as convalescent carriers. Even though they may appear fit and healthy they can still spread the bacteria, both to other people and to food.

If at any time you suffer from the symptoms of food poisoning whilst in work you MUST NOT HANDLE FOOD. You must immediately report your illness to your supervisor and you may not re-enter a food handling role until you have been clear from illness for a minimum of 48 hours.

Even then, you could still be a convalescent carrier. This is why you must wash your hands thoroughly before handling food and follow all best food safety practices whilst in the workplace. 

Common Types of Food-borne Illness

The most common source of food-borne illness is bacteria, of which there are many. Some illnesses are caused by viruses, such as norovirus. Viral and bacterial illnesses take effect in different ways and so must be controlled differently. Fungal illnesses are most often caused by the ingestion of poisonous mushrooms, though compared to bacterial and viral food-borne illnesses this is rare. Chemical-derived food-borne illnesses are chiefly the result of cross-contamination; the improper use of cleaning agents and/or storage issues are often to blame.

Bacteria 

E-coli 0157

Clostridium

Salmonella

Listeria

Campylobacter

Bacillus

Dysentery

Staphylococcus

Viral

Norovirus

Fungal

Mycetism

Others

Allergens

E-coli 0157

The E-coli bacteria is commonly found in the human intestines and is mostly harmless; however, the E-coli 0157 strain is extremely harmful. This virulent strain can cause vomiting and diarrhoea that can ultimately lead to kidney damage and failure. Onset times are relatively quick - anything from a few hours to 2-5 days - and once symptoms present themselves they progress rapidly. Outbreaks have been known to result in multiple deaths. Sources of E-coli 0157 are infected cattle (i.e. raw meat), unpasteurised dairy produce, raw vegetables, and from the guts of infected persons.

Clostridium 

Although a common cause of food poisoning Clostridium can often be ingested with no adverse effects. However, if symptoms do show they can be very serious.

There are two main types of Clostridium bacterium: Clostridium perfringens and Clostridium botulinum.

C. perfringens is the less serious of the two, causing abdominal pain and diarrhoea.

C. botulinum can lead to respiratory problems (difficulty breathing) and even paralysis.

Both strains of Clostridium are widely found in our surroundings - in the soil, in the air, in water, in vegetation, etc. - and are commonly linked to foods including vegetables, raw meat, fish and poultry.

Salmonella 

Salmonella is closely related to E-coli bacteria, harming both humans and other animals. Symptoms include stomach pain, vomiting, diarrhoea, and fever, and incubation times vary from a few hours to 2 days after infection. Salmonella can found in raw meat and poultry, unpasteurised dairy products, polluted water, and raw unwashed vegetables, as well as in the faeces of humans and other animals.

Listeria 

Listeria is most commonly associated with unpasteurised cheeses, but other high risk foods include pâté, salad vegetables and many soft cheeses. Listeria bacteria can lead to listeriosis, which typically presents itself with flu-like symptoms but can then lead on to other more serious conditions, including meningitis, miscarriage amongst pregnant women, and possible death within vulnerable groups. It is for this reason that expectant mothers are advised to avoid eating the aforementioned foods. Listeria can have a long incubation period of up to 70 days so symptoms may take some time to appear after eating contaminated foods.

Campylobacter 

Campylobacter is the most common cause of acute bacterial diarrhoea. It is found in animals and poultry, and so the most common sources are raw meat, raw chicken, and unpasteurised milk. Symptoms include persistent abdominal pain and diarrhoea (often bloody), after a typical incubation period of around 3-5 days.

Bacillus cereus 

B. cereus is part of a huge genus of bacteria. It is spore-forming, meaning that it can produce endospores that are particularly resilient to extreme heat and cold. For this reason the cooking temperature of high-risk foods must be carefully monitored.

The diarrhoeal form causes diarrhoea and gastrointestinal pain, and can have an onset time of 8-16 hours (for this reason it is sometimes referred to as ‘long-incuba

Dysentery 

Dysentery is an intestinal illness transmitted through faecal matter. As such it presents itself in the form of diarrhoea - in some cases blood and mucous will also be present. Other symptoms include abdominal pain and fever.

Infection tends to occur in institutional settings where hygiene is difficult to monitor, such as primary schools. The bacteria are transferred

Norovirus 

Norovirus (sometimes known as ‘Norwalk virus’ or the ‘Winter vomiting bug’) is a viral illness that can cause vomiting, diarrhoea, fever and abdominal pain.

Due to its highly infectious nature - spreading readily from person to person, and also through contaminated water - Norovirus is most problematic in closely-populated settings, such as schools, hospitals, offices and prisons. Onset times are typically 1-3 days, with symptoms lasting 3-4. Although not a severe illness (most people recover within a week), it can be more serious when contracted by the vulnerable groups.

Mycetism 

Mycetism is the name given to mushroom (fungi) poisoning. Commercially grown fungi rarely pose a threat; the vast majority of Mycetism cases are the result of ingesting wild mushrooms.

Many wild mushrooms are poisonous. They should not be gathered and eaten unless they have been positively identified as a safe variety. Most toxic mushrooms will cause vomiting or diarrhoea, without any long-term damage; some, however, are highly toxic or even deadly. The onset times of some poisonous mushrooms can be as little as a few minutes to several weeks after ingestion.

Allergies 

Allergens are anything that can cause an allergic reaction within a susceptible person.

Common allergic conditions include Coeliac disease (allergy to gluten), irritable bowel syndrome (a gastrointestinal disorder, often resulting in food intolerances), and lactose intolerance (intolerance to a sugar found in certain dairy goods).

People who suffer from allergies will normally be very aware what goes into their food, often asking questions about ingredients and cooking methods. The presence of certain allergens - such as peanuts, dairy and gluten - should be clearly stated on a menu or product

Allergens

Any food can cause an allergic reaction, with the symptoms varying according to the severity of the allergy. However, EU legislation identifies 14 foods that MUST be mentioned on food labelling: 

• Wheat
• Eggs
• Peanuts
• Soya
• Milk
• Gluten
• Sesame Seeds
• Nuts
• Mustard
• Lupin
• Fish
• Shellfish
• Celery
• Sulphur Dioxide and Sulphites

Allergen Precautions

MIn order to minimise the risk of allergic reactions to food you must be awareof everything that goes into it. 

• Information about how products are made and what ingredients have been used must be made available.
• Cross-contamination must be avoided:

• Store high risk (allergenic) foods separately

   • Always wash your hands before and after handling allergens

   • Use separate utensils and equipment when processing allergens

   • Clean and disinfect (sanitise) all work areas that have been used to prepare allergenic foods

• Follow company policy on providing consumers with safety assurances.
• Know your ingredients - and which are potential allergens.

Allergic Reaction Symptoms

• Allergic reactions can cause anything from a mild stomach upset, headache or nausea to swollen tissue, vomiting and respiratory failure.
• A person with a severe allergy will normally take precautions, possibly carrying vital information on their person (often in the form of a bracelet, neck chain or, increasingly, a smart phone app), and may well carry emergency medication (such as an ‘EpiPen’ adrenaline injection).
• When working with food you must take food allergy seriously: a severe allergy could kill. Some allergic reactions can take hold within seconds, others may take several hours. Symptoms vary, but commonly will cause one or more of the following:
• Skin rash
• Fever
• Sweating
• Blurred vision
• Nausea
• Vomiting
• Stomach pain
• Headache
• Swollen tissue - especially the tongue, throat and lips
• Tingling sensation
• Difficulty breathing/speaking

A severe reaction can cause a person to go into anaphylactic shock, which can be life-threatening.

Food Intolerance

Food intolerance, like food allergy, takes place when certain foods are eaten by people who have an intolerance to that particular food.

Where an intolerance differs from an allergy is in its severity.

An intolerance will often cause considerable discomfort to the sufferer. It is not, however, life-threatening.
Whereas only a trace of an allergen is enough to cause an allergic reaction, in general a much larger amount is needed to trigger an intolerance.

Summary

• Food-borne illness can be caused by eating contaminated food.
• It can be life-threatening.
• The onset time can vary from minutes to days.
• It is caused by microorganisms, chemicals and natural toxins.
• Vulnerable groups: the elderly, the very young, the ill, pregnant women.
• Symptoms include nausea, diarrhoea, vomiting and stomach pain.