Understanding Common Microbiological Food Contaminants and Their Health Risks

According to the World Health Organization (WHO), each year unsafe food causes 600 million cases of foodborne diseases and 420,000 deaths. Thirty percent of foodborne deaths occur among children under 5 years of age. WHO estimates that 33 million years of healthy lives are lost due to eating unsafe food globally each year, and this number is likely an underestimation. Below are some common examples of food-borne pathogens.

Salmonella

Overview: Salmonella is typically associated with poultry and eggs but has occasionally been present in fruits and vegetables due to contamination while growing in fields.

Health Risks:

• Symptoms: Diarrhoea, fever, abdominal cramps, and vomiting.
• Severe Cases: Infections can lead to hospitalisation and, in extreme cases, may be fatal, particularly in young children, the elderly, and immunocompromised individuals.

Escherichia coli (E. coli)

Overview: E. coli is a diverse group of bacteria, with some strains being harmless and others causing severe illness. The most notorious strain, E. coli O157, is a toxin-producing strain from a family known as STEC (Shiga toxin-producing Escherichia coli). In food, it is often linked to undercooked minced beef (think rare burgers) and raw milk. Other common routes to infection are from handling live animals and from contaminated water.

Health Risks:

• Symptoms: Severe stomach cramps, diarrhoea (often bloody), and vomiting.
• Severe Cases: Some infections can lead to hemolytic uremic syndrome (HUS), a serious condition affecting the kidneys, which can be life-threatening.

Listeria monocytogenes

Overview: Listeria monocytogenes is a bacterium found in soil, water, and some animal feces. It thrives in low temperatures and wet environments, making it particularly challenging to control in food factories. Although killed by cooking, post-cooking contamination is easy if not controlled, and products that are not cooked further by the consumer are particularly risky for certain consumers.

Health Risks:

• Symptoms: Fever, muscle aches, and gastrointestinal symptoms.
• Severe Cases: Listeriosis, caused by ingestion of L. monocytogenes, can lead to meningitis and septicemia, especially in those with weakened immune systems. In pregnant women, it can cause miscarriage, stillbirth, or severe infection in newborns.

Norovirus

Overview: Norovirus is a highly contagious virus that can be transmitted through contaminated food, water, or surfaces. It is often associated with shellfish, fresh produce, and ready-to-eat foods. It is resistant to alcohol-based hand sanitisers and is still infectious in very low doses, hence its ability to rapidly spread through an enclosed population, for example, a cruise ship or school.

Health Risks:

• Symptoms: Acute gastroenteritis, characterised by nausea, vomiting, diarrhoea, and stomach pain.
• Severe Cases: Dehydration is a significant risk, especially for the very young, elderly, and those with underlying health conditions.

Campylobacter

Overview: Campylobacter is commonly found in raw or undercooked poultry, unpasteurised milk, and contaminated water. It is one of the leading causes of bacterial foodborne illness worldwide.

Health Risks:

• Symptoms: Diarrhoea (sometimes bloody), fever, and abdominal cramps.
• Severe Cases: In rare instances, Campylobacter infection can lead to Guillain-Barré syndrome, a serious condition affecting the nervous system.

Preventative Measures and Best Practices

Preventing microbiological contamination in food involves rigorous adherence to hygiene and safety practices throughout the food supply chain:

• Proper Cooking: Ensure that food, especially meat and poultry, is cooked to the recommended temperatures to kill harmful bacteria. In factories and eateries, ensure that a robust HACCP system is in place and rigorously followed.
• Hygiene: Wash hands, utensils, and surfaces thoroughly to prevent cross-contamination.
• Storage: Follow pack instructions for proper storage temperatures to inhibit bacterial growth.
• Education: Stay informed about food recalls and safety alerts from regulatory agencies such as the FSA alert system.

Conclusion

Understanding common microbiological contaminants and their health risks is crucial for supporting food safety and protecting public health. A good resource in the UK is the Food Standards Agency website: Food Standards Agency

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The article is written by our Food Manufacturing and Testing Specialist and General Manager at One Scientific — A Tentamus Company , Dominic Long .?

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Please feel free to connect with Dominic Long on LinkedIn for more insights on food safety and industry best practices and reach out to us at [email protected] to work together!