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Editorial: Of salads and safety

Of salads and safety

April 24, 2008  By Marg Land

I was chatting with a friend of mine a few weeks ago when the subject of “food poisoning” came up – literally.

I was chatting with a friend of mine a few weeks ago when the subject of “food poisoning” came up – literally.

She had hosted a play-date (an excuse for kids to come visit and trash your home while their exhausted mothers try to relax with a VERY strong coffee) a few days previously, complete with a nutritious lunch. Within 24 hours, the phone calls started – first one, then two, then seven of the participants had fallen ill with some form of gastrointestinal hell. The ailment didn’t last too long – 12 to 36 hours at the most – but it was a rough experience while it lasted. A few of the mothers raised the possibility of something being “off” with the noon meal.


“I can’t imagine it being that,” my friend said. “Everything was really well cooked.”

Having queasily squirmed my way through a fair share of food safety talks delivered rather graphically by Dr. Doug Powell (past University of Guelph associate professor and current scientific director of the International Food Safety Network at Kansas State University), I asked the key question – Was there a salad served?

“Yes. Why?”

One thing I’ve learned from Dr. Powell’s presentations – besides never to eat unpackaged mints or candies left by restaurant cash registers – is that most cases of foodborne illness can be traced back to contaminated leafy greens, such as lettuce or spinach. Given the physical structure of the leaves, the plant’s close proximity to the ground and the fact leafy greens are typically not heated or cooked (a step that can help to eliminate pathogens), it’s possible for salads to be bad for your health.

“But the salad was triple washed,” my friend said.

According to recent research by scientists with the U.S. Department of Agriculture, not all washing techniques for fresh cut produce are equal. In the case of wash water reuse – a common practice with some growers and processors – organic matter can quickly accumulate in the wash water, compromising the efficacy of any sanitizers also being used.

“It is generally known that water reuse can cause water quality loss,” said Dr. Yaguang Luo, a research food technologist with the USDA who also headed the study. He added that results from his study should define relationships among produce wash operations, water quality and product quality.

Increasingly, my friend’s experience is becoming all too common. In fact, a recent study by the U.S. Center for Disease Control and Prevention (CDC) shows that outbreaks of foodborne illnesses linked to leafy greens are on the rise, increasing faster than rates of consumption.

The CDC study was presented during the 2008 International Conference on Emerging Infectious Diseases, held mid-March in Atlanta, Ga., and involved a review of all foodborne disease outbreaks reported from 1973 to 2006. Of the 10,421 incidents reported in that time, 502 (five per cent) outbreaks, 18,242 (6.5 per cent) illnesses, and 15 (four per cent) deaths were linked to leafy greens. Of those leafy green reports, 196 (58 per cent) were related to Norovirus, 35 (10 per cent) involved Salmonella, and 30 (nine per cent) were linked to Escherichia coli 0157:H7 (not sure what the other 23 per cent involved). From 1986 to 1995, leafy green consumption in the U.S. increased by just over 17 per cent from the previous 10-year period. During the same time period, the rate of foodborne illness outbreaks connected to leafy greens increased 60 per cent. From 1996 to 2005, consumption jumped another nine per cent while leafy green illness outbreaks increased 39 per cent.

What does this mean? According to CDC researchers, foodborne illnesses linked to leafy greens are on the rise and not just because people are eating more of them. They suggest that efforts by local, state and federal agencies to control leafy green outbreaks should span from the point of harvest to the point of preparation.

Some steps have been made to just that. Following the U.S. illness outbreak linked to contaminated spinach in 2006, the U.S. Food and Drug Administration ordered processors to implement Hazard Analysis and Critical Control Points (HACCP) systems throughout their supply chains.

We’ll have to wait and see what effect that move has on the statistics.

What about the Canadian experience? There has been a movement among growers and processors to voluntarily incorporate increased food safety measures, including HACCP. In the case of some grocery chain suppliers, it has been mandated.

Traceability has also become a larger issue with growers and processors becoming involved.

But if the U.S. experience is any example to go by, it’s just a matter of time before we find out whether these measures have been enough.

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