biological contamination

Biological Contamination & its Sources

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Food is, undoubtedly, the most pertinent source of energy and nutrition for all living things. It exists in many forms and is converted into many as well. 

These living things include microorganisms. In order to make their own food, they break down complex food structures into smaller, simpler components. And in the process of doing so, they also happen to decompose organic matter, as a part of nature.

biological contamination

Due to their decomposing properties, if they somehow end up in our food, a phenomenon occurs that is known as biological contamination which is not good news for fellow human beings; because this contamination is the cause of most foodborne diseases and illnesses.

Contamination, in broader terms, is used to define the process of making by-products by unwanted microorganisms. Such microorganisms are known as Pathogens. While some microorganisms like certain types of bacteria can be useful in adding to a shelf-life of food, others’ effects can prove life-threatening.

‘Of the approximately 600 million cases of foodborne illnesses all over the world, a majority of this portion is caused by biological contamination.’ Fooddocs

Contamination is, therefore, completely unwanted and results in the wastage of food as, once contaminated, it cannot be consumed by any individual as it could to lead to serious health-threatening (and in some cases, life-threatening) medical conditions.


Biological contamination refers to the event wherein any other living organism, mostly microorganisms, contaminate a food product.

Types of Biological Contamination

The biological contamination of food may show any of the following signs:

  • Foul smell
  • Discolouration
  • Loss of structural integrity
  • Drastic change in flavour

However, some types of contamination may go undetected through the human eye due to its limited physical presence, in case it is caused by a bacterial toxin or virus.

Some of the most commonly known pathogens that cause bacterial contamination are mentioned below:

  • Bacteria: This type of pathogen is present in most types of food and have the ability to thrive in most conditions as well. Some of these may survive and spread through food handlers, some may be present in raw food, and some spread mostly through contaminated water.  

Examples: Staphylococcus aureus and sail-borne bacteria.


  • Fungi (molds and yeasts): Contamination caused by fungi appears as
  • Green and white circles
  • Cottony patches (white or black)

This type of contamination is mostly seen in conditions that may appear challenging to bacteria (such as acidic foods). They produce microbial communities that make them susceptible to observation and can spread through spores floating in the air, that too very fast. Their visibility makes it easy to separate contaminated food hence, it is less likely to cause foodborne diseases.

Example: Alternaria, Aspergillus and Candida.

  • Virus: Viruses are the most common illness-causing foodborne pathogens that are transferred through food. Some of these can also travel through water and contaminate seafood, vegetables and fruits which can also be eaten raw, hence, the chances of them causing illnesses is rather high. It houses one of the biggest 6 foodborne illnesses causing pathogens, the Norovirus.

Example: Nanovirus, Norovirus.

  • Parasites: These pathogens are very tiny and cannot be seen by the naked eye. These are mostly present in raw meats. These are the most harmful as they have the ability to harm their hosts, which they target for their nutrition. They may be transferred from host to host or through food.

Example: Trichinella spiralis

Most contaminations are transmitted through fecal routes and water systems. Therefore, efficient monitoring detection and prevention are the keys to a healthier environment. Also, biological contaminations cannot withstand extreme temperatures. 

This is why it is eminent for food businesses to ensure practice of proper cooking and storage. This significantly reduces the risk of an attack of a pathogen.

5 Most Common Contaminants in Food

‘There are at least 250 identified foodborne illnesses known to the food industry; the majority of these illnesses are attributed to biological contamination.’ – The Centers for Disease Control and Prevention

Although all contaminants cause threat to human health through food, in addition to Norovirus, the following are ranked to cause the most numbers of foodborne illnesses every year. These are few of the 250 known causes of biological contaminations.

  • Listeria monocytogenes: Causes Listeriosis and is commonly found in dairy products due to its ability to survive in low temperatures.
  • E. coli: Known as the main cause of traveler’s diarrhea and can harm health even if it is in very small amounts. It commonly travels through contaminated water and raw meat.
  • Salmonella: This pathogen causes at least 1.35 million cases of foodborne illnesses in the US alone. It is found in poultry products, vegetables and other raw materials.
  • Clostridium perfringens: It spreads through contaminated water and is widely found in the intestines of humans.

The 4 Main Sources of Biological Contamination

Contamination through pathogens can be introduced in the food processing system at any point. The four main sources of biological contamination include,

  • Water and soil
  • Cross-contamination
  • Pests
  • Raw materials

Soil and Water: When it comes to agriculture, following a strict hygiene regime and bearing in mind the environmental safety standards is imperative. Because even the slightest slip can put the consumer’s health and ecology at risk. Biological contaminants or pathogens can easily spread through the following ways:

  1. The use of manure as a fertilizer
  2. Through irrigation
  3. Water streaming systems
  4. Lack of water filtration
  5. Consumption of contaminated food crops

Cross Contamination: Equipment used in the kitchen and food handler’s also increases chances of foodborne illnesses. Various pathogens are also present on human skin, which is why improper food-handling is known to be the fastest source of biological contamination.

Pests: These are like homes to various types of pathogens and most foodborne illness causing contaminants. When they leave behind droppings, hair, nails, severed body parts, or merely have slight contact with food, the pathogens that they carry can be transmitted.

Raw Materials: Almost all raw materials consist of microorganisms on their surfaces, which is why so much significance is given to proper agricultural practices.

Effects And Symptoms Of Biological Contamination On Public Health

Consumption of biological contaminants can inflict serious harm to health and, in some cases, it may even cause death. 

‘Every year, at least 3,000 consumers die in the US, whereas 420,000 deaths occur worldwide due to foodborne illnesses.’ – Fooddocs

Individuals struck with a stronger, more harmful pathogen show more severe symptoms than the rest. Additionally, individuals who are at higher risk of getting infected by contamination are:

  • Children under the age of 5
  • Pregnant woman
  • The elderly
  • Individuals with immune deficiency 

The ones suffering from a biological contamination may show the following symptoms:

  • Fever
  • Nausea
  • Vomiting
  • Fatigue
  • Diarrhoea

Ways to Detect Biological Contamination

The effect harmful microorganisms have on health may be severe, but it is rather difficult to detect as it is often not visible to the naked eye. Hence, the use of test kits and advanced machines has made it easy for medical experts to detect their presence.

The type of detection method used at a time depends on the urgency and the specificity of the contamination. Some may only require a yes or a no answer, while others might demand a deeper analysis. But what is most important for food businesses is the efficiency of the method at hand to know which type of contamination their products are more susceptible to.  

Below are stated some of the advanced procedures to detect biological contamination:


Once a pathogen contaminate certain food, the effect of their presence becomes apparent on its surface. In order to have a more accurate observation, medical specialists use the following methods,

  • Microbial Plating: In this method, the samples are diluted and plated in a growing medium and then observed to see if there is any presence of a pathogen. It is widely used to quantify the contaminants and analyze whether they possess any real threat. This helps to countercheck the results of more advanced detection methods.
  • Advanced test kits: This method is faster than the microbial plating method. Its results are more specific and can generate accurate results within hours. Its time-saving feature makes it rather costly as compared to other methods. Different kits detect different toxins or pathogens.


The Takeaway

All-in-all, no matter what the quantity or the quality of food may be while leaving the site, it is all equally in danger of a biological contamination that may take place whenever and wherever it wishes. Hence, food businesses need to be very vigilant when it comes to preventing the attack of harmful pathogens and use the right methods to detect, analyze and eradicate their presence in order to ensure a healthier environment. These can effectively be done by the use of digital technologies and software solutions. Folio3 is the best software provider in the food industry. The software solutions help keep track of each and every activity performed at the facility. 

About Folio3 AgTech Practice

Folio3 is a Silicon Valley based Digital Transformation partner for entrepreneurs and Fortune 500 companies with a special focus on digitization of Agriculture, Production and Companion Animal industry. Having worked with some of the world’s leading animal health companies, cattle associations, cow-calf operators, cattle feeders, beef processors and beef marketing companies, we have the design and development expertise required to help you digitize your manual procedures and practices, whether you’re a farm or a ranch owner, veterinarian, feedlot manager, nutritionist, or processing plant owner, we have got you covered.

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