There are "significant lapses" in the way the United States Food and Drug Administration verifies the safety of fresh spinach, a new U.S. government report says.

"It appears that FDA is inspecting high-risk facilities infrequently, failing to take vigorous enforcement action when it does inspect and identify violations and not even inspecting the most probable sources of many outbreaks," said the report by the House committee on oversight and government reform released last week.

The report, titled "FDA and Fresh Spinach Safety," adds that these inspections of packaged fresh spinach facilities are the agency's primary means of checking product safety.

The investigation was prompted by a September 2006 outbreak of E. coli strain O157:H7 that caused more than 200 illnesses, including that of an Ottawa woman, and three deaths that were ultimately traced back to packaged fresh spinach.

There have been at least 20 U.S. outbreaks of this strain of E. coli tied to fresh spinach or lettuce in the past 12 years. E. coli, or Escherichia coli, is a species of bacteria that lives in animal intestines.

The committee found that the FDA's current scope of investigation "appears too narrow to capture the sources of an E. coli outbreak."

"The outdated statutory sanitation standard severely limits the scope of FDA's ability to adequately prevent many outbreaks," read the report. "Laboratory sampling can detect some microbial contaminations, but cannot prevent many outbreaks."

Inspectors look at the interior of the facility, but not the exterior, which is believed to be the source of the 2006 outbreak. Officials said the water at the facility in San Benito County, Calif., was likely contaminated by cattle feces, pig feces or river water.

In addition to "significant shortfalls" in the scope of inspection and testing, the report also cited difficulties in enforcing corrections to unsanitary conditions.

The committee found that the FDA observed objectionable conditions during nearly half its inspections of fresh spinach packing facilities, with the most common complaints linked to plant sanitation, plant construction and worker sanitation.

The report said the FDA took "no meaningful enforcement action," such as warning letters, seizures or injunctions, and did not follow such practices at the source of the 2006 E. coli outbreak, where lab testing indicated microbial contamination.

When further investigation is deemed necessary, the report found the FDA had difficulty in accessing relevant material or firm records, as the agency lacks the authority to force companies to hand over the information. In at least eight cases, including with the facility at the source of the outbreak, the agency was denied access.

The report also noted that packaged fresh spinach facilities were inspected once every 2.4 years rather than once a year, which is the FDA's inspection goal.

The committee said that inadequate funding and resources for food safety activities at the FDA may contribute to the problems with spinach safety inspections.