Keeping crops clean in NZ

Posted by Josette Dunn on 3rd November 2010

The New Zealand Food Safety Authority (NZFSA) is conducting a new study into how water and natural fertilisers – such as manures, biosolids and compost – are used by the horticultural industry.

NZFSA specialist advisor Marion Castle says the study will help growers continue to produce safe fruits and vegetables and avoid problems that have hit the fresh produce industry overseas. The study will also look at how contaminants from these sources that might be introduced to fresh produce are currently controlled.


Internationally, outbreaks of foodborne illness have resulted from contaminated irrigation water, contaminated water used to wash fresh produce, improperly treated manures, animals defecating on fresh produce, and poor personal hygiene practices.

NZFSA’s new study will look at organic and conventionally grown fresh produce. It will focus on fresh produce intended to be consumed raw, or as a raw dried or semi-dried product.

“Cooking at high enough temperatures for long enough to kill pathogens will prevent most foodborne illness. Not all fresh produce is cooked before use and can be used in salads or eaten as cut-up fruit. Any pathogens that are present at high numbers could make people sick,” Marion says.

Fresh produce-related food safety issues are rare in New Zealand, but many high-profile foodborne illness outbreaks have been linked to fresh produce overseas. In the United States, for example, there have been outbreaks associated with contaminated products including spinach, raspberries and tomatoes.

In 2009 NZFSA conducted a survey of illness-causing bacteria in fresh ready-to-eat fruit and vegetables at retail. The survey indicated a very low level of contamination in New Zealand produce, and pathogens were only detected in two of 900 samples. Both were Salmonella-contaminated lettuces from the same grower.

As part of this new study NZFSA will be talking with growers about their current practices.

“We are very interested in what growers do to manage risks, such as following good agricultural practices and using assurance programmes. This information will contribute to future risk profiles and guidance materials for growers and help them grow fresh produce that is as safe as it can be,” Marion says.

Note to the editor:

Reported produce-related food safety outbreaks in New Zealand are rare. Instances include an outbreak of Hepatitis A associated with raw blueberries in 2002. In 2005 consumption of raw carrots was identified as the probable cause of an outbreak of Salmonella Saintpaul.

The majority of New Zealand growers and processors have adopted Good Agricultural Practices and some produce companies have put food safety programmes in place for production and processing of fresh produce.