Food and Water Safety During a Biological Threat

Biological agents can contaminate food and water — either deliberately (bioterrorism) or incidentally (contaminated water systems, disrupted food supply chains during crisis). Protecting what you consume is one of the most direct ways to prevent ingestion of harmful agents. This guide covers how to protect existing supplies, how to treat potentially contaminated water, and what food safety practices reduce biological risk.

How Biological Contamination Reaches Food and Water

Route	Examples	Prevention
Direct contamination of open water sources	Agent released into reservoir or river	Use only sealed/treated water
Contaminated supply chain	Processing facility contamination	Use sealed, commercially packaged food
Airborne fallout	Aerosolised agent settles on food/surfaces	Keep food covered; wash produce
Person-to-person via food handling	Infected food handler	Handwashing; avoid shared food
Animal reservoirs	Plague-infected rodents near food	Pest control; sealed storage

Protecting Your Water Supply

The Hierarchy of Safe Water

During a biological emergency, use water sources in this priority order:

1. Sealed, commercially bottled water — the safest option; biological agents cannot penetrate intact sealed containers.
2. Water from a municipal supply that is still being treated — if authorities confirm treatment is ongoing, tap water remains safe.
3. Previously stored water in sealed containers filled before the emergency.
4. Treated water from potentially contaminated sources (see treatment below).
5. Untreated water from open sources — do not use unless no other option exists and it has been treated.

Water Treatment for Biological Contamination

Boiling is the most reliable method for biological contamination:

• Bring water to a rolling boil for at least 1 minute (3 minutes at elevation above 2000 metres)
• Boiling kills virtually all biological pathogens including bacteria, viruses, and parasites
• Boiling does not remove chemical contamination — only use this for biological threats

Chemical disinfection (if boiling is not possible):

• Household bleach (5–8% sodium hypochlorite): 8 drops per litre of clear water; 16 drops for cloudy water. Wait 30 minutes before drinking.
• Water purification tablets: follow manufacturer instructions
• Both methods are effective against bacteria and many viruses but less effective against some protozoa (Cryptosporidium)

Filtration alone is insufficient for most biological agents — filters must be complemented with chemical treatment or boiling.

⚠️ Anthrax spores are resistant to standard chlorine treatment at typical water supply concentrations. If anthrax contamination of the water supply is specifically suspected, use sealed bottled water only.

Container Hygiene

• Use only clean, sealed containers for storing safe water
• Label containers clearly — "CLEAN WATER" and the date treated
• Do not use the same containers that previously held contaminated water without thorough cleaning and disinfection
• Bleach solution (1:10) for container decontamination before use

Protecting Your Food Supply

Sealed vs. Unsealed Food

Food Type	Biological Safety During Emergency
Intact, sealed cans and jars	Safe — contamination cannot penetrate sealed packaging
Sealed plastic pouches and foil packages	Safe if seals are intact
Open or exposed dry goods (flour, rice)	Cover and protect; consider bagging
Fresh produce (unwashed)	Wash thoroughly with clean water
Fresh produce (pre-washed)	May be contaminated if washed in contaminated water
Cooked food	Safe if cooked to temperature in clean environment
Raw animal products	Cook thoroughly; assume surface contamination

Handwashing Before Food Preparation

In a biological emergency, handwashing before touching food is the single most important food safety practice:

1. Use soap and clean water — 20 seconds minimum
2. Wash before every instance of food preparation, not just when hands are visibly dirty
3. Use gloves for food preparation if hands may have been exposed

Cooking as Decontamination

Thorough cooking kills biological agents:

• Meat: internal temperature of 75°C/165°F
• Eggs: until yolk and white are firm
• Any food suspected of biological contamination: boil or cook at high temperature for appropriate duration

Cooking does NOT neutralise toxins that some bacteria have already produced (e.g., botulinum toxin at some concentrations, Staphylococcal toxin). When in doubt about a food's safety, do not eat it.

Food Storage

• Keep sealed food in its original, intact packaging
• Store away from areas that may have been directly exposed to biological material
• After a suspected aerosolised release, wipe down sealed packaging with a damp cloth before opening
• Discard any food that was open or uncovered during a suspected release

Recognising Food or Water Contamination

You may not be able to detect biological contamination in food or water through smell, taste, or appearance. However:

• Unusual taste, smell, or appearance in treated water is a warning sign — do not consume
• Unusual cloudiness, colour in water sources — use alternate sources
• Multiple people becoming ill with similar gastrointestinal symptoms after consuming the same food or water — this is an epidemiological indicator

Report to public health authorities if multiple people become ill with similar symptoms after consuming shared food or water.

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Quick Reference

Situation	Safest Water Option	Water Treatment
Normal tap (treated supply)	Safe to drink	No treatment needed
Uncertain supply	Sealed bottled water	Use as-is
Open source (well, stream)	Treat before drinking	Boil 1 min; OR 8 drops/L bleach + 30 min
Anthrax suspected	Sealed bottled only	Cannot be treated adequately

Food Category	Safe?	Action
Sealed cans/jars	Yes	Open and eat
Open/exposed dry goods	Unknown	Cover; wash before use
Fresh produce	Treat as contaminated	Wash with clean water; peel
Cooked food (clean environment)	Yes if cooked to temperature	Cook thoroughly