Eat Your (Canned or Frozen) Spinach!

On September 14, 2006, the U.S. Food and Drug Administration (FDA) issued a warning to consumers concerning an outbreak of E. coli O157:H7 in fresh spinach. This is a severe strain of E. coli that causes diarrhea. Most healthy adults who contract it can recover within a week, but the elderly and young children can develop a form of kidney failure called Hemolytic Uremic Syndrome (HUS). In extreme cases, this form of E. coli can be lethal. As of September 19, 2006, the FDA reported 131 cases of illness due to E. coli infection, with 20 cases of HUS, 66 hospitalizations, and one death. These cases covered 21 states.

Although the FDA is recommending that all fresh spinach and salad blends containing fresh spinach be discarded, it does say that this strain of E. coli can be killed by cooking the spinach at 160 degrees for 15 seconds. Although cooking the spinach seems to be within the capability of most consumers, FDA apparently feels that the potential consequences of infection are too great to justify that course. FDA also warns against the dangers of cross-contamination of other foods when handling the spinach.

As of September 19, the FDA had not determined the cause of the outbreak, or the geographic source of the affected spinach. Most of the spinach produced in the United States is grown in California, particularly in the Salinas Valley. Two California companies have announced voluntary recalls of their products containing fresh spinach. According to the FDA, since 1995 there have been 19 outbreaks of foodborne E. coli O157:H7 in lettuce and leafy green vegetables. Many of these cases were traced back to the Salinas Valley.

Although the cause has not been determined conclusively, a few possibilities have been identified. It seems most likely that the source of the E. coli was animal manure, or contaminated water. According to an FDA official, rivers and creeks in the Salinas watershed are occasionally contaminated with E. coli. These waterways occasionally flood farmland, and although FDA has recommended that producers discard produce that has been in contact with floodwater, that does not always happen.

Another possible cause that has been identified by at least one food science expert is the practice of beginning processing of fresh produce in the fields. While final processing is still done in a plant, some coring and removal of outside leaves of lettuce is done in the field in order to reduce transportation costs. This increase in efficiency carries the risk of exposing the produce to contaminated water or manure in the field.

While there have been several E. coli outbreaks in the produce industry in recent years, this one may be the biggest headache for produce companies, groceries, and consumers due to its scope. This case also represents some of the worst publicity for the food industry in recent years. In addition to questions about the safety of vegetable production and processing, it also raises the issue of traceability of a product through the food chain. The ability to trace agricultural products from the consumer back through the processing and distribution chain has become an important issue in agriculture, in the notable cases of mad-cow disease and genetically modified crops. Export markets are demanding an increasing level of traceability and product identification.

The total economic damage done to the spinach industry, and to the vegetable industry overall, remains to be seen. The direct damage in terms of lost sales will be steep for the spinach industry. According to USDA, in 2005 the total value of the U.S. fresh spinach crop was $157.5 million. The value of spinach for processing was $10.5 million. It is possible that some potential losses can be recouped by processing spinach that normally would have been sold in the fresh market, but that will be limited by processing capacity. The value of the fresh spinach that was already harvested and in the distribution chain will be lost, as well. To put the numbers into perspective, the total value of fresh-market vegetables grown in 2005 was $9 billion. Therefore, spinach represented only 1.7% of the fresh vegetable market.

In addition to the direct damage of lost fresh spinach sales, the fresh produce industry as a whole may suffer due to the loss of consumer confidence and associated lost sales. The indirect damage will take longer to develop, and may be impossible to measure.

The industry also is likely to face more stringent food safety rules, such as discarding produce grown in fields where flooding has occurred. New processing rules may also be implemented, and a system for tracking product through a distribution network may be needed. The incident could cause a shift from consumption of fresh produce back toward more canned and frozen produce. All this will translate into higher costs for the produce industry.