Biological and chemical contamination of food

What is a food contaminant?A food contaminant is the presence of substances in food which may lead to illness in the consumer.

Food contaminants include biological contaminants: bacteria, fungi, parasites, algae, or viruses.

or

Chemical contaminants: traces of pesticides or growth hormones, detergents, and disinfectants.

How do food contaminants get there?Food usually becomes contaminated through: environmental contamination or bad handling.

Why is food contamination a problem?Food contamination leads to food-borne illness or food borne diseases.

These are illnesses such as: Campylobacteriosis, Botulism, Listeriosis, but can also include Cancer

Often these illnesses are only uncomfortable, but in some cases these illnesses can lead to death.

Hidden danger at the barbequehttps://www.youtube.com/watch?v=pdKHCVGSg3Q

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What are the biological causes of foodborne illnesses, and how do we recognise them?

As stated earlier, biological contaminants include: bacteria, fungi, parasites, algae, or viruses.

The bacteriasSalmonella, Botulism, Campylobacter Jejuni, E.Coli, and Listeria are the common bacterial contaminants of food.

Let’s look at each, in turn, and recognise:

the causes of contamination, the

symptoms of illness

and how to prevent illness.

Salmonella: bacterialCauses:

food handlers that do not wash their hands

or handling: reptiles, baby chicks, or small rodents that carry the bacteria

Food is typically contaminated with human or animal waste.

Salmonella: bacterialSymptoms:

Normally show up 8-72 hours after eating contaminated food:

Symptoms include: •diarrhea, •fever, •abdominal cramps, •nausea, and •vomiting.

Salmonella: take care withFoods to be cautious of: raw meat, poultry, seafood, raw eggs, and fruits and vegetables (particularly imported varieties that may not have been washed in clean water).

How to be safe? Cook foods thoroughly!

Botulism: bacterialCauses: a bacteria that causes poisonous toxins to form when it is deprived of oxygen (e.g., items in cans or bottles). Or food that has become contaminated with infected soil.

Botulism: bacterialSymptoms: Normally begin 12-36 hours after infection

Symptoms include: •Difficulty swallowing or speaking

•Blurred or double vision

•Nausea

•Vomiting and abdominal cramps

•Paralysis

Botulism: take care withFoods to be cautious of: home-canning products

any food in a cracked or dented can.

How to be safe: boil any canned product.

Campylobacter Jejuni: bacterialCauses: the bacteria lives in the intestines of healthy birds

illness is caused by eating raw or undercooked meat

Campylobacter Jejuni: bacterialSymptoms: Occur 1-10 days after infection

Symptoms include: •Muscle pain

•diarrhea

•abdominal pain and cramps

•fever

•vomiting

Campylobacter Jejuni: take care withFoods to be cautious of: eating undercooked chicken or other food that has been contaminated with juices dripping from raw chicken, as this is the most frequent source of this infection

How to be safe? Thoroughly cook all foods

E. Coli: bacterialCauses: •meat contaminated by intestinal bacteria

•unpasteurized milk

•contaminated water (human and animal waste can contaminate the water we wash vegetables in)

•Person-to-person (contact with food that a contaminated person has handled)

E. Coli: bacterialSymptoms: Normally occur 2-9 days after infection

•Diarrhea, which may range from mild and watery to severe and bloody

•Abdominal cramping, pain or tenderness

•Nausea and vomiting, in some people

E.Coli: take care withFoods to be cautious of: •Ground beef (minced, carne picada)

•unpasteurized milk

•fresh vegetables

How to be safe? •Order meat well-done,

•wash products thoroughly,

•drink pasteurized milk

Listeria: bacterialCauses: •often found in dairy products made with unpasteurized milk

•Raw vegetables that have been contaminated from the soil or from contaminated manure used as fertilizer

•Infected animal meat

• some processed foods—such as soft cheeses, hot dogs and deli meats that have been contaminated after processing.

Listeria is particularly harmful to babies

Listeria: bacterialSymptoms: •Fever

•Muscle aches

•Nausea

•Diarrhea

Listeria: take care withFoods to be cautious of: •Ready-to-eat deli meats and hot dogs

•Refrigerated pâtés or meat spreads

•Refrigerated or smoked seafood

•Raw sprouts

•Unpasteurized soft cheese (queso fresco, Feta, Brie, Camembert

How to stay safe? •avoid high-risk foods if pregnant •wash and cook food thoroughly •avoid refrigerated, raw meats.

Are there other ways food becomes biologically contaminated?

So far, we have looked at bacterial contaminants. However, there are other biological contaminants. These include: viruses, parasitic nematodes and worms, and protozoal contaminants.

We will continue this section on biological contaminants with common examples of these.

Hepatitis A: viralCauses:

•occurs when a person ingests even tiny amounts of contaminated fecalmatter.

•when you eat raw shellfish from polluted water

•ingesting contaminated water (even ice!)

•sexual contact

The hepatitis A virus infects liver cells and causes inflammation

Hepatitis A: viralSymptoms:

•Normally occur within several weeks of being infected

•Yellowing of the skin and eyes (jaundice)

•Loss of appetite

•Fatigue

•Fever

Hepatitis A: take care with

Foods to be cautious of:

•raw shellfish •raw products

How to stay safe? Get vaccinated!

•Peel fruits andvegetables

•Wash hands often

Hepatitis A: where?

Toxoplasmosis: protozoal (parasitic)Causes: •often found in mammals and birds

•Infected animal meat

•Consuming undercooked or raw meat that is infested with the parasite.

Risk to pregnant women:

If you become infected for the first time just before or during pregnancy, you can pass the infection to your baby (congenital toxoplasmosis), even if you don't have signs and symptoms yourself.

Toxoplasmosis: protozoal (parasitic)Symptoms:

•Fever

•Swollen lymph nodes

•Headache

•Fatigue

Toxoplasmosis: take care withFoods to be cautious of: •Raw or undercooked meat

How to stay safe? •Wear gloves when you garden or handle soil.

•Don't eat raw or undercooked meat.

•Wash kitchen utensils thoroughly.

•Wash all fruits and vegetables.

•Don't drink unpasteurized milk.

•Cover children's sandboxes.

Trichinosis: parasitic nematodeCauses: •often found in pork infested with the larvae of the nematode.

Trichinosis: parasitic nematodeSymptoms: •Fever

•Vomiting

•Diarrhea

•Sensitivity to light

•Pink eye (conjunctivitis)

Trichinosis: take care withFoods to be cautious of:

•Raw or undercooked pork.

How to stay safe?

•Larvae may be killed by the heating or irradiation of raw meat.

Anisakiasis: parasitic worm (Anisakis worm)Causes: •often found in infected fish

•if you consume undercooked or raw fish containing the larvae of the anisakis worm

Anisakiasis: parasitic worm (Anisakis worm)Symptoms: •Hives

•Swollen eyelids and lips

•Abdominal pain

•Vomiting

•Diarrhea

Hives

Swollen Eyelids

Anisakiasis: take care withFoods to be cautious of: •raw fish •Sushi, •temaki, •nigiri, etc.

How to stay safe?

•Do not eat raw or undercooked fish or squid.

•Freeze fish or squid before cooking.

Chemical and Physical contaminationThe final two ways in which food often becomes contaminated are: chemical and physical.

Chemical contamination of food•Traces of pesticides •Traces of growth hormones •Detergents •Disinfectants

•They can produce food-borne disease and even cancer.

Physical contamination of foodContaminants: •Pieces of broken glass •Pieces of metal •Plastics (microplastics)

•It can produce damage when swallowed by accident.