Every time there is a food safety outbreak with fresh fruits and vegetables, some journalist or lobby group will call up and say something like, “we want to do some sampling for E. coli or Salmonella and fresh produce.”
And every time, Chapman or I will walk the person through the limitations with testing, especially in fresh produce.
New studies by the New Zealand Food Safety Authority (NZFSA) highlight the limitations. In one, two out of 900 samples tested positive for Salmonella in lettuce, both from lettuces from the same grower.
In a related study, none of the chemical residues detected were of health concern, although 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.”
Properly structured sampling programs are essential to validate that food safety programs are working. But testing is not enough.