Microbiological Contamination

What Microbiological Contamination covers

Microbiological Contamination is examined in Unit A2 1 Option B, Food Safety and Quality — one of two options. It covers Salmonella and Campylobacter, Listeria and Escherichia coli, high-risk foods for food poisoning, microbial control by producers and manufacturers and microbial control in catering and at home.

The 5 subtopics

Each one has its own page.

• Salmonella and CampylobacterWhere Salmonella and Campylobacter come from, the foods and symptoms linked to them, the control of Salmonella in eggs, cross-contamination from raw chicken and industry controls.Open →
• Listeria and Escherichia coliWhy Listeria grows in the fridge, high-risk foods and groups, listeriosis in pregnancy, Escherichia coli O157, haemolytic uraemic syndrome and the 2005 South Wales outbreak.Open →
• High-risk foods for food poisoningWhat makes a food high risk, cooked rice and Bacillus cereus, oysters, raw eggs, unpasteurised dairy, salads and sprouts, the temperature danger zone and bacterial growth calculations.Open →
• Microbial control by producers and manufacturersFarm biosecurity, clean livestock, pasteurisation and UHT, high-care areas, chilling, modified atmosphere packaging, canning, hurdle technology and microbiological testing.Open →
• Microbial control in catering and at homeThe 4 Cs, colour-coded boards, cooking and cooling temperatures, personal hygiene, stock rotation, fridge storage, pest control, cleaning and safe defrosting and leftovers at home.Open →

What you need to know

Answer each one before you reveal it.

Take Microbiological Contamination further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Salmonella vs Campylobacter

  Salmonella: a rod-shaped bacterium from poultry and eggs, controlled in UK flocks by vaccination. Campylobacter: a spiral-shaped bacterium that rarely grows in food but infects at very low doses.

• Listeria monocytogenes vs Escherichia coli O157

  Listeria monocytogenes: a bacterium that grows at fridge temperatures and threatens unborn babies. Escherichia coli O157: a toxin-producing bacterium from cattle that can cause kidney failure in children.

• Pasteurisation vs Sterilisation

  Pasteurisation: mild heating that kills pathogens but leaves some spoilage organisms alive. Sterilisation: intense heating that destroys all microorganisms and their spores.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What kind of organism is Salmonella, and where is it usually found?

   Model answer

   Salmonella is a rod-shaped bacterium that lives in the intestines of animals, especially poultry. People are infected through contaminated food, water or contact with animals.

2. 2

   Which foods are most commonly linked to Salmonella food poisoning?

   Model answer

   Raw and undercooked poultry, eggs and raw meat are the main sources. Unpasteurised milk, salad vegetables and sprouted seeds can also be contaminated.

3. 3

   Describe the symptoms of salmonellosis and when they appear.

   Model answer

   Salmonellosis causes diarrhoea, abdominal cramps, fever and sometimes vomiting. Symptoms usually begin 12 to 72 hours after eating and last four to seven days.

4. 4

   Why is salmonellosis more dangerous for some groups than others?

   Model answer

   Infants, older people and people with weakened immune systems are more likely to become seriously ill. Salmonella can spread from the gut into the bloodstream and then needs antibiotic treatment.

5. 5

   How was Salmonella in UK eggs brought under control?

   Model answer

   The British Lion scheme introduced vaccination of laying hens against Salmonella in 1998. Salmonella in UK eggs fell sharply afterwards.

6. 6

   What did the FSA change in 2017 about eating runny eggs?

   Model answer

   The FSA advised that vulnerable groups can safely eat British Lion eggs raw or lightly cooked. The change reflected the very low Salmonella risk in eggs from vaccinated flocks.

What is inside Levo

Six ways to work the same material.

Microbiological Contamination revision questions

What does Microbiological Contamination cover in CCEA A-Level Nutrition and Food Science?

5 subtopics: salmonella and campylobacter, listeria and escherichia coli, high-risk foods for food poisoning, microbial control by producers and manufacturers and microbial control in catering and at home. Each one has its own page with questions and model answers.

How is Microbiological Contamination organised?

By the CCEA 3310 specification, subtopic by subtopic, so it matches the order you are taught it in.