Table of Contents

Introduction

Foodborne illnesses—commonly referred to as food poisoning—are infections or intoxications caused by consuming contaminated food or drink. According to the World Health Organization (WHO) and the NSW Food Authority, foodborne illnesses can be caused by bacteria, viruses, parasites, or chemical substances entering the body via contaminated food. The outcomes range from mild stomach upset to severe and even fatal infections, particularly among vulnerable groups.

Definition and Scope

Foodborne illnesses encompass a broad range of conditions. As defined by Australian health authorities, they involve any illness caused by eating food contaminated with harmful pathogens or toxins. Symptoms can vary widely depending on the cause but often include nausea, vomiting, diarrhoea, and abdominal pain. Severity ranges from short-lived discomfort to long-term complications or hospitalisation.

Causes and Transmission

Pathogens can contaminate food through several pathways:

Bacteria, such as Salmonella or Listeria, multiply in improperly stored or cooked food.
Viruses, like Norovirus, can spread through contaminated water or infected food handlers.
Parasites may infect undercooked meat or produce.
Toxins, produced by bacteria or introduced through chemicals, can lead to rapid onset food poisoning.

Contamination is often linked to:

Undercooked meat
Poor personal hygiene among food handlers
Cross-contamination between raw and cooked foods
Inadequate refrigeration or reheating

The Most Common Foodborne Pathogens in Australia

Australia reports thousands of foodborne illness cases annually. Below are the most common pathogens responsible:

Salmonella

Salmonella is frequently found in raw eggs, undercooked poultry, and unpasteurised dairy. Symptoms include:

Diarrhoea
Fever
Abdominal cramps

Incubation: 6–72 hours
Duration: 4–7 days
Outbreaks in Australia have been linked to contaminated egg products and mayonnaise.

Campylobacter

Primarily found in raw or undercooked poultry, Campylobacter is one of the leading causes of bacterial gastroenteritis in Australia.

Symptoms: Diarrhoea (sometimes bloody), fever, nausea, abdominal pain
Complications: Rare cases may lead to Guillain-Barré syndrome, a neurological disorder.

Incubation: 2–5 days

Listeria monocytogenes

Listeria poses serious risks to pregnant women, the elderly, and immunocompromised individuals. It is commonly found in:

Soft cheeses
Ready-to-eat meats
Pre-packaged salads

Symptoms: Flu-like symptoms, nausea, diarrhoea, and, in severe cases, septicaemia or miscarriage.
Incubation: Up to 70 days.

Norovirus

Often dubbed the “winter vomiting bug,” Norovirus spreads rapidly through person-to-person contact and contaminated food such as:

Shellfish
Prepared foods handled by infected staff

Symptoms: Vomiting, watery diarrhoea, stomach cramps
Incubation: 12–48 hours

Escherichia coli (E. coli)

Not all E. coli strains are harmful, but E. coli O157:H7 can cause serious illness. Found in:

Raw or undercooked beef, especially mince
Contaminated produce
Unpasteurised milk

Symptoms: Severe abdominal cramps, bloody diarrhoea
Complications: Haemolytic Uraemic Syndrome (HUS)
Incubation: 1–10 days

Other Notable Pathogens

Clostridium perfringens: Linked to improperly cooled meats.
Vibrio: Associated with raw oysters and warm waters.
Shigella: Transmitted through contaminated water or food handled by infected persons.

Examples of High-Risk Foods Linked to Foodborne Illness

According to the NSW Food Authority, certain food groups are especially prone to contamination:

Poultry and Eggs

Risks: Salmonella and Campylobacter
Issues: Undercooking, raw egg use in sauces or desserts, and improper kitchen hygiene.

Seafood and Shellfish

Risks: Norovirus and Vibrio
Safety tip: Source seafood from reputable suppliers and cook thoroughly.

Deli Meats and Soft Cheeses

Risks: Listeria
Avoid long refrigeration and always check use-by dates.

Raw or Undercooked Beef

Risks: E. coli contamination, particularly in ground beef or rare steaks.
Prevention: Cook beef to a safe internal temperature of 71°C.

Fresh Produce

Risks: E. coli, Salmonella, Listeria
Contamination can occur through irrigation water or unhygienic handling.

Foodborne Outbreaks in Australia: Real-Life Examples

Notable Salmonella Outbreaks

2018: Over 200 cases traced to contaminated egg products in NSW.
2020: Bakery chain outbreak linked to undercooked pastries with raw egg fillings.

Listeriosis in Vulnerable Populations

2019: Several cases among elderly Australians were traced to pre-packaged salads.
Hospitals and aged care homes were impacted, highlighting the need for stringent food safety practices.

Norovirus in Food Service Settings

Cruise ships and restaurants have reported outbreaks due to poor hygiene and infected food handlers.
In one Queensland case, over 130 patrons fell ill after consuming contaminated salad.

Symptoms and Health Effects of Foodborne Illness

Common Symptoms

Nausea
Vomiting
Diarrhoea
Abdominal pain
Fever

Severe or Long-Term Complications

Reactive arthritis: May follow a Campylobacter or Salmonella infection.
Kidney failure: Associated with E. coli O157:H7.
Miscarriage or stillbirth: Linked to Listeria during pregnancy.

Seek medical attention if symptoms are severe or persistent, especially for infants, pregnant women, older adults, and people with weakened immunity.

Diagnosing and Reporting Foodborne Illness in Australia

Medical Diagnosis

Diagnosis typically involves:

Stool samples
Blood tests
Patient history

General Practitioners (GPs) play a crucial role in identifying and reporting cases.

Government Reporting and Tracing

Authorities such as the NSW Food Authority and ACT Health investigate outbreaks through:

Interviews
Laboratory testing
Trace-back methods

Reporting helps prevent further infections and identify unsafe food sources.

How to Prevent Foodborne Illness

Safe Food Handling

Wash hands before and after handling food
Use gloves appropriately
Clean surfaces and utensils frequently

Learn more about proper food handling and hygiene through accredited food safety training.

Proper Cooking and Storage Temperatures

Cook poultry to 75°C
Keep fridge below 5°C and freezer at -18°C
Cool hot foods from 60°C to 21°C within 2 hours, and down to 5°C within 4 hours

Cross-Contamination Prevention

Use separate boards for raw and cooked foods
Sanitize knives and benches
Avoid placing cooked food on surfaces that held raw meat

Regulatory and Workplace Responsibilities

Food Safety Training Requirements

Australian food laws mandate training for those handling food. Many roles require completion of a Food Safety Supervisor course or a Food Handler Certificate, depending on state legislation.

Employer Obligations

Employers must:

Maintain hygiene policies
Monitor staff health
Ensure proper storage and preparation procedures
Report any suspected contamination incidents

Summary and Key Takeaways

Foodborne illnesses are a serious public health issue in Australia. Understanding how pathogens like Salmonella, Listeria, and Norovirus contaminate food—and how to prevent this—is vital for food workers and consumers alike.

Key reminders: