European E. Coli
Western Europe is facing its own “spinach moment” on the heels of an E. coli outbreak that killed 32 and sickened more than 3,000. The illnesses affected primarily Germans or visitors to Germany, but the regional transport of fruits and vegetables throughout the European continent has led to a devastating drop in fresh produce consumption.
On May 24, German officials reported three deaths and a significant number of people sickened by Shiga toxin-producing E. coli. Subsequent testing found that the STEC serogroup O104:H4 strain, a unique one that first appeared in 2000, was responsible. O104:H4 is known to cause severe manifestation of symptoms, and in this outbreak it has been responsible for 817 cases of hemolytic uremic syndrome (HUS) and more than 2,500 non-HUS cases.
The first case of STEC E. coli O104:H4 was believed to be on May 2 and hundreds more were reported in each of the following weeks. By the time information was released to the public, nearly three weeks had passed and the European Centre for Disease Prevention and Control could not identify a source for the pathogen. It was initially reported as early as May 25 that lettuce, tomatoes and cucumbers could be the cause, and German officials warned consumers to be especially careful when consuming these products.
The warning for the fresh vegetable products was the result of an investigation into the foods consumed by sickened individuals, conducted by the Robert Koch Institute May 29-June 2. The results of 46 surveyed individuals showed that 84 percent had consumed salads, compared to 47 percent of the healthy control group. Three-quarters of those sickened had consumed cucumbers, and 80 percent had eaten tomatoes. All were higher than the controls, and statistically associated the products with the outbreak. A second study by the Frankfurt Health Office and the Hessian Land Testing and Investigation Office for the Health Care Sector on a cluster of cases found that employees that had eaten salad from the salad counter of one cafeteria were seven times more likely to be sickened than those that did not consume salad. No other foods in that study were linked.
On May 26, the German health authority identified cucumbers from Spain as the source, a claim that was disputed by the Spanish Agriculture Minister the next day.
During the investigation, trading partners could only react with the information available to them, as evidenced by the Russian government banning the import of all vegetables from Germany and Spain on May 30. On May 31, German health officials retracted their claim that the Spanish cucumbers caused the outbreak, which led to Spain and the Netherlands demanding compensation for lost vegetable sales. In the midst of the confusion, Russia widened its import ban to all fresh vegetables from all 27 European Union member countries.
It wasn’t until June 5 that regional health officials in the Lower Saxon region of Germany announced they believed the source of the pathogen to be vegetable sprouts grown in the area. By June 8, the number of new infections began decreasing and the rising death toll had slowed, and on June 10 Germany officially identified sprouts as the source and finally lifted its warning on tomatoes, lettuce and cucumbers and after talks with European Union trade officials, Russia also lifted its ban on fresh vegetables.
While two early studies identified salads or fresh tomatoes or cucumbers as the source of the infection, a detailed, recipe-based study by the Robert Kock Institute narrowed the focus down to sprouts. In this study, five groups of people in travel groups or food clubs – 112 in total with 19 sickened by the E. coli outbreak – were extensively interviewed about their meals, and their answers were verified by receipts and menus. The investigators then questioned the restaurant operators about food preparation and ingredients, and the menu items were confirmed through photographs taken by group menus at those restaurants. Based on the study, the institute found that customers that ate sprouts were 8.6-fold more likely to come down with the illness associated with E. coli. Additionally, the researchers found that all the 19 sick individuals in the study had consumed sprouts.
As of June 10, no test has found E. coli O104:H4 in retail product, but sprouts grown in the Lower Saxony region can explain 26 of 55 disease clusters, according to the European Centre for Disease Prevention and Control. The sprout grower is working with German and European Union food safety agencies to pinpoint the source. The company has provided its food safety measures. Testing was underway in mid-June on samples from the growing operation, but the ECDC was confident that it had found the source even if tests came back negative for E. coli O105:H4.
Product from the sprout grower has been pulled from the market and health officials are looking into the source of contamination, which is believed to be seed or water.
“Even if the outbreak pathogen has not been detected in any samples thus far, the accumulated evidence strongly points to this producer as the source of the outbreak. The federal and state authorities will perform further investigations and analyses of supply and distribution chains to investigate whether contaminated seed for sprout production may be present in other companies or could reach the market,” according to an ECDC statement.
-By Scott Christie, Managing Editor
-Published in the July 2011 issue of Fresh Cut
