Peppery pourpier from the Lake Geneva region.

The Center for Science in the Public Interest (CSPI), a non-profit, consumer advocacy group, often referred to as the “American food police”, says the leafy greens we are encouraged to eat every day can in fact be the most dangerous of all vegetables. Over the last 20 years, there has been some 363 outbreaks and 13,568 illnesses due to green leafy foods alone.

According to Dr. Steve Swanson of the US Centers for Disease Control, lettuce is only second to ground or minced beef in cases of E. Coli. Snopes gives a good explanation of how all this happens, and many suggest that we lay off pre-washed, bagged salads until more is know about exactly how greens are contaminated.

One thing is almost sure: one of the reasons salad is particularly more high risk than other vegetables is that we most often eat it raw. So wash your salad, and then wash it again. Don’t just spray it. Wash it in a basin or sink, and change the water several times.

The other high risk food is eggs, numbering 352 outbreaks in the US in the last 20 years, with 11,163 cases of illness reported.

If we want to make a “top ten” list, the other culprits, in order, are tuna, oysters, potatoes, cheese, ice cream, tomatoes, sprouts and berries.

The problem with leafy greens in particular is that they can be contaminated in the fields, before they ever hit the supermarket, so until there is an outbreak, it is not known that the food is contaminated. The origin of the vegetables is then traced, and the products are recalled, but this can take time, and until the epidemic becomes public, people continue eating what they’ve already bought.

Eggs are more likely to contain salmonella.

In Switzerland, the Federal Department of the Home Affairs, reports an average 50 to 70 cases of E. Coli infection per year, and in 2007, 1,800 cases of salmonella and 6,000 cases of campylobacter, another foodborne disease. There are regular outbreaks of Norovirus every winter, but statistics are not available. These outbreaks generally occur in institutions like resthomes and clinics.

They recommend taking preventive measures, especially with regard to meat. Always wash your hands after touching meat, and if you have touched meat, before touching salad in particular, since it is eaten raw. Salmonella is often found in raw eggs, so make sure to use only fresh eggs, keep your eggs as cold as possible, or else make sure and buy pasteurized eggs.

When traveling, follow the golden rule of “Cook it, peel it, or forget it” (sorry, no salad when traveling in exotic or underdeveloped countries) and above all, maintain personal hygiene. Wash your hands regularly: after going to the toilet, before meals, before you start cooking, after touching raw meat, and after contact with animals.

Norovirus is a bit apart in that it is difficult to eliminate with ordinary cleaning products. Stronger products such as bleach are required.

And always wash and rewash green leafy foods, even if they have been pre-washed. Bon appétit?