About this guidance
This guidance has been developed by New Zealand Food Safety based on international guidance, scientific evidence, and best practice.
The guidance applies to hives or honey that have been in contact with flood waters, not for hives or honey that have been damaged by rainfall. Hives and honey that have been damaged by heavy rain and have not come into contact with flood water will not be contaminated and are deemed safe and suitable for human consumption.
Information on this page is also available in a document.
Download guidance for harvesting flood-affected honey for human consumption [PDF, 162 KB]
Contamination in flood waters
During a flooding event, contamination in flood waters will be widespread. Flood waters may be contaminated by sewage, dead animals, decaying plants, and chemicals. They may also contain pathogenic microorganisms and physical debris such as glass, wood, and metal. Chemical contamination can come from many sources, including buried farm waste, submerged vehicles and mechanical equipment, stored pesticides and herbicides, and damaged manufacturing facilities.
Managing food safety risks of honey affected by flood water
Honey that was harvested and packed in sealed containers prior to the flooding is safe and suitable for human consumption. If containers have been submerged and the integrity of a container seal cannot be ascertained, then the honey from those containers is considered to be contaminated.
Honey from hives that did not come into direct contact with flood waters is also safe for human consumption. Honey harvested from hives that were immersed in flood waters cannot be sold for human consumption. This is because the range of contaminants that could have been present in the flood water is so broad that it is not feasible to use laboratory tests to check that the honey is safe.
However, if only shallow parts of the hives have been affected by flood water, and the honey and bees are unaffected, this honey would be deemed safe and suitable. Any hive boxes impacted by flood waters should be replaced as soon as practicable to ensure other risk factors, such as mould and other insects, do not spread to the rest of the hives.
Summary of the main points
- New Zealand Food Safety recommends a situational risk assessment to determine whether honey from flood-impacted areas can be processed and used for human consumption.
- Harvested honey that was packed prior to the flooding is considered safe for use provided that sealed containers retain their integrity, and exterior surfaces are cleaned.
- Honey that has come into direct contact with flood waters cannot be used for human consumption.
- Honey harvested from hives that were immersed in flood waters will not be able to be used for human consumption.
- Honey from hives that were near flood waters but not immersed is not a food safety risk.
Microbiological risks of honey
- Honey is considered to be a microbiologically safe product as it has a low pH, low water activity, and contains hydrogen peroxide and other antimicrobial substances that prevent the growth and survival of the major foodborne pathogens.
- The only known pathogen of concern in honey is Clostridium botulinum. Honey contaminated with spores of C. botulinum has been implicated in infant botulism.
- Honey that is ready for harvest is hygroscopic. This means that honey may draw moisture and become contaminated with any pathogens that were present in contaminated flood waters if the hives were flooded.
- Flooding of hives could also result in an increased incidence of C. botulinum linked to the growth and sporulation of these microorganisms in dead bees and pupae. However, this is an increased risk for infants only and, as it is generally advised to not give honey to infants, this risk is already managed.
- It may be useful to measure the pH and moisture content or water activity of harvested honey to help in assessing its food safety.
Chemical and toxicological risks of honey
- There is no known acute health risk from chemicals in flood waters that would render honey that has been harvested from hives that were immersed in flood waters to be inherently unsafe. On the other hand, there is no way to demonstrate absence of all conceivable toxic contaminants across all products. For this reason, testing is unable to provide a way to save honey that was or may have been exposed to flood waters.
- Good hygiene practices and principles, as well as organoleptic (such as assessment of flavour, odour, appearance) and other quality control measures should generally guide the collection and use of honey.
- No maximum limits for contaminants exist in New Zealand food standards that could usefully guide testing in situational assessments in this flood scenario.