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Food Contamination - An Overview

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5 min read


Contaminated food can make people sick and cause serious illness. It can occur anywhere from a farm field. Read below to know more.

Written by

Dr. Shuchi Jain

Medically reviewed by

Dr. Basuki Nath Bhagat

Published At October 3, 2022
Reviewed AtApril 4, 2023


Everyone deserves healthy, safe food. But sometimes, food can bite back and cause illness. Infectious organisms or toxins can contaminate food at any stage- production, processing (growing, harvesting, storing), distribution (shipping), and preparation. It can happen even in the kitchen if the food is improperly cooked or handled. The contamination of food leads to several foodborne diseases and food poisoning.

What Is Food Contamination?

Food contamination refers to the spoilage of food by another substance, such as microorganisms (bacteria, viruses) or toxic substances that make it unfit for consumption.

A food contaminant can be chemical, microbial, physical, or allergenic.

  • Chemical contaminants include - pesticides, bleach, salts, toxins, etc.

  • Microbial contaminants include - bacteria and viruses such as E. coli, norovirus, etc.

  • Physical contaminants include - hair, plastic, jewelry, pieces of plastics, etc.

  • Cross-contamination is when all the above contaminants get into food, making it unsafe to eat.

What Are the Sources of Contamination?

The main routes of contamination are as follows:

  • Improper handwashing.

  • Ill suited storage and temperature.

  • Water, air, dust, sewage, animal waste, and insects are contaminated.

  • Cross-contamination.

  • Raw material contamination from soil, sewage, pesticides, animals, etc.

What Is Food Poisoning?

Intake of contaminated food leads to foodborne illness, commonly known as food poisoning.

Contamination can happen at any time, at any given point. These contaminants (bacteria, viruses, parasites) lead to food poisoning. Common foodborne germs are - Norovirus, Salmonella, campylobacter, E. coli, and staphylococcus aureus. The signs and symptoms of food poisoning usually appear within hours after eating contaminated food. However, sometimes it might take several days to weeks.

The symptoms include:

Let Us Understand the Journey of Food - From Farm to Fork:

Before understanding food contamination, let us first know what a food chain is and how we get the food on the dining table from the farms (the food journey). The food journey from farm to fork (on the dining table) is complex. Food goes through many stages - production, processing, distribution, and preparation. Finally, the food is served at the dining table, and we get to eat it.

Food takes a long journey, touches countless people, and contamination can occur at any point during this chain.

Let Us Have a Glimpse of the Food Production Process and How Food Is Contaminated During This Process.

1. Production: The first stage in the food cycle is production. Production refers to growing plants and raising animals for food. Domestic animals and plants assist in the production of food on farms.

How Food Gets Contaminated During the Production Process?

We have often heard about the contamination of fruits and vegetables on farms. How does this happen?

  • For irrigation, the fields are sprayed with contaminated water. It results in the contamination of fruits and vegetables, even before they are harvested. That is why people are shifting toward organic farming and prefer organic fruits and vegetables as they lack pesticides and other contaminants.

  • If the reproductive organs of egg-laying animals are infected, they may contaminate the egg yolk even before it is laid. This is another means of contamination.

  • Sometimes fishes acquire toxins from smaller creatures they eat, resulting in transmission of contamination to the ones who eat those fishes.

2. Processing: It is the second stage, where plants/animals are transformed into a form that can be bought and used as food. Different foods have different methods for processing food.

For example, grinding grain to produce flour, Pasteurizing milk, slaughtering animals, etc.

How Food Gets Contaminated During Processing?

  • Usually, we process food by washing it first. Contaminated water and ice used in washing and chilling is the first mode of contamination.

  • We process the food by keeping it on a surface. If germs already contaminate the surfaces, the contamination will also be transferred to the food.

  • During the slaughtering process, if the animal's intestine already has germs, they will also be there in the final meat product. That's another way of contamination.

  • After processing, the food is stored. If the storage bins had germs in them, they could spread to the food also, as the food touched the surface.

3. Distribution: The food is now distributed after production and processing. In this process, the food is taken from the farm and made available to the public (customer) through the local markets, supermarkets, restaurants, etc.

For example - Subway patty. It is first taken from the large manufacturing plant, trucked to the supplier warehouse, stored for a few days, shipped to a local distributor, and finally to the restaurant chain.

Now imagine the food being prepared in a large manufacturing plant. There, it can contaminate equipment/food processing tools, labor, packaging, storage and temperature issues, etc.

A lack of proper temperature and surface contamination might contaminate it when it is trucked.

If kept for a few days in a warehouse, the bacteria might multiply in n numbers, making it hazardous for consumption.

4. Preparation: This is the last and final stage where the food is made available for consumption. The step occurs in the kitchens.

It involves the following steps:

  • A recipe and the ingredients needed.

  • Heating/ freezing

  • Serving it on a plate.

  • For parcels - opening a package and eating it.

We will see how food is contaminated during this process.

  • If the chef/coworkers are sick and do not wash their hands regularly, there are chances that they might spread the germs by touching the food.

  • If the cook uses a cutting board and knife to cut raw chicken and then uses the same knife and board to slice raw veggies, there are chances that the germs of raw chicken might get onto the vegetables.

  • Some microorganisms grow well in colder temperatures. If those prevailing bacterias come in contact with some other food, they, in turn, contaminate the food.

Mishandling the food cycles the contamination process without a pause and increases the likeliness of foodborne diseases and food poisoning.

What Are the Measures Taken to Prevent Food Contamination?

The Food Industry -

  • The food industry should record food from its source to its destination.

  • Strictly keep a check on food safety laws and regulations and put them into action.

  • Make people aware of the products that are linked to outbreaks.

  • Develop strategies for the food at the most significant risk for contamination.

  • Laboratory testing and disease reporting should be done periodically.

The Vendors -

  • Proper management practices to store and deliver food should be followed.

  • Certified (food safety) managers should be hired in restaurants and other food stores.

  • Follow ethical guidelines for the storage and handling of food products.

  • Keep records of the food and food ingredients and where they came from.

General Public -

  • Wash hands and clean utensils before every use.

  • Separate poultry/seafood from ready-to-eat food.

  • Cook the food properly.

  • Refrigerate the food that requires a cold temperature.

  • Don't prepare food when ill.

  • Take extra care of children, pregnant women, poor individuals, and older adults.


Each year many people suffer from food poisoning, which makes them sick and sometimes the condition can become life-threatening. Changes in food patterns and eating habits are also contributing factors to contamination. Contamination can occur anywhere: farm fields, storehouses, transport vehicles, or kitchens. One should follow simple food safety procedures such as cleaning, separating, cooking, and chilling. Wash hands regularly and cleans the surfaces often. Do not cross-contaminate. Cook the meals at the right temperature. Refrigerate promptly. Thus one should follow the food safety precautions and help society prevent foodborne contamination.

Source Article IclonSourcesSource Article Arrow
Dr. Basuki Nath Bhagat
Dr. Basuki Nath Bhagat

Family Physician


food contamination
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