Pre-washed spinach alleged as E. coli source at Sequoias Pre-washed spinach alleged as E. coli source at Sequoias (January 28, 2004)

By David Boyce

Almanac Staff Writer

A study conducted by the county's public health agency suggests that packaged pre-washed spinach was infected with the E. coli bacteria that caused the death of resident Alice McWalter and the sickness of 15 other residents in October 2003 at The Sequoias retirement community in Portola Valley.

While a definite determination of the source of the outbreak awaits investigations by state and federal agencies, a recent six-page study from the disease control and prevention unit of the San Mateo County Health Services Agency said that 12 cases -- including that of Ms. McWalter -- were likely due to eating the raw spinach.

"We found that just rinsing and washing it does not always do the trick," said Dean Peterson, the county's director of environmental health. The keys to prevention, he said, are uncontaminated irrigation water and proper restroom facilities and cleansing habits where vegetables are picked and packaged.

The other four Sequoias infections were likely "secondary cases," the study said, meaning that victims had not caught the disease from eating the spinach, but by cross-contamination from others who had. E. coli can be spread by touch from improperly washed hands.

Scientific and medical literature have not previously linked pre-washed spinach with E. coli infections, the study said. None of the food handlers at The Sequoias had symptoms or tested positive for the bacteria.

Working assumptions about vegetables are evolving, Mr. Peterson said. For some time, raw chicken has been assumed to be contaminated with salmonella bacteria. The new view is that all food should be seen as potentially contaminated, he said.

The Sequoias has also adopted that view. Since the outbreak, all food is washed, including pre-washed food, said Sequoias spokesman Mel Matsumoto. Food suppliers were "put on notice" about food quality at the time of the outbreak, he said.

"A quality product includes being free of bacteria," Mr. Matsumoto said. Legal action is not being taken against food suppliers in this case, he said, but he noted that The Sequoias has not given up its right to pursue it.

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