Comprehensive health check on fresh fruit 'n' veg
Results from three New Zealand Food Safety Authority (NZFSA) studies reaffirm the safety of New Zealand food. None of the chemical residues detected were of health concern and one instance of bacterial contamination has been investigated.
Nevertheless, NZFSA principal advisor for chemicals Dr Paul Dansted says he is disappointed with results from this year’s Food Residue Surveillance Programme (FRSP), which targets food likely to show up problems. This year’s focus was on spinach, celery, ginger and garlic. “A significant number of samples had levels over the maximum residue limit (MRL) which is used for monitoring purposes, but it’s important to stress that dietary intake assessments on the non-compliant food showed none posed a health or food safety concern.”
Eight out of 27 celery samples and four out of 24 spinach samples had residues that were over the limit. There were none over the limit in 50 samples of garlic, but ginger had 11 samples out of 39 over the limit.
“Celery and spinach can be more vulnerable to persistence of chemical residues,” Dr Dansted says. “Because of their shape, residues that wash off in the rain can collect in the base of the plant. We expected to find some problems, but this is not good enough. We will take regulatory action to ensure better compliance in future.”
NZFSA also conducted a survey on illness-causing bacteria in fresh fruit and vegetables after several high-profile international outbreaks of foodborne illness related to contaminated produce. Only two out of 900 samples tested positive, both from lettuces from the same grower and contaminated with Salmonella.
NZFSA microbiologist Dr Roger Cook says: “Leafy vegetables can easily pick up bacteria of animal origin, and this is a reminder to growers that they need to have controls in place to prevent contamination. And despite the low risk associated with fresh produce, people should remove outer lettuce leaves and thoroughly wash the rest before eating to get rid of any bacteria that might be present.”
Finally, quarterly results from the five-yearly Total Diet Study continue to show the wider New Zealand food supply presents no health concern. Over the year, the study puts more than 120 commonly eaten foods into the lab to assess New Zealanders’ dietary exposure to chemical residues, contaminants and selected nutrients.
This quarter, 61 foods bought in Auckland, Napier, Christchurch and Dunedin were prepared for eating before being tested. Senior programme manager Cherie Flynn says new testing equipment used for the 60,000 analyses turned up more traces of pesticides and other chemical contaminants than previously, but not in terms of being above MRLs or other monitoring limits.
“The lab is now able to detect residues at a much lower level than in previous studies. It’s like using a newer digital camera to get a clearer, more detailed picture,” she says.
There were a small number of samples where a compound was over the maximum residue limit, but were not a health risk. Two related to imported grapes, five to bread which was highly likely to be made with imported grain or flour, and one to celery.
Cherie says there were 9 detections of very low levels of endosulfan, a chemical withdrawn for use in New Zealand in January 2009. Reasons for its detection include presence on food being imported from countries where it is allowed, and lingering environmental presence. It is not necessarily due to New Zealand growers using endosulfan.
Note to Editors on residues:
Celery and spinach are problematic because they are both are so-called ‘minor crops’, which are not widely grown in New Zealand. Consequently there is a smaller range of agricultural compounds available for growers to use on this type of produce compared with other crops. ‘Off-label’ use of pesticides registered for other crops is allowed, but any residue must be low (less than 0.1 parts per million or 100 parts per billion).
The shapes of celery and spinach also lend themselves to collect residues in the base of the plant that might otherwise wash off in the rain, which we had plenty of this season. For the FRSP the whole plant is tested unwashed and untrimmed, so the results obtained are worst-case scenarios.
Safety assessments show that an average-sized adult (weighing 75kg) could eat 136g a day of the celery with the highest residue for the whole of their life with no effect. The average amount of celery people eat a day is just 29 grams.
For celery, one sample had four residues over the limit, one had three residues, and three had two. The other three samples had just one residue above the MRL. The other 19 samples were compliant.
Note for Editors on pathogens:
Produce-related food safety issues 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.
Internationally outbreaks have been caused by contaminated irrigation water, poor hygiene practices, improperly treated manures and feral pigs defecating on produce.
In New Zealand growers and processors have adopted good agricultural practice and some produce companies have put food safety programmes in place for production and processing of ready-to-eat food produce.
For Food Residue Surveillance Programme (FRSP) results see:
Food Residues Surveillance Programme
For Total Diet Study (TDS) third quarter results see:
2009 New Zealand Total Diet Study
For answers to common questions about agricultural compound residues in food see: