(CNN) -- The company that inspected a Colorado cantaloupe farm at the center of a deadly listeriosis outbreak ignored federal regulators' "best and most timely" advice on processing produce, a congressional committee has found.
The FDA cited "serious design flaws" and a "lack of awareness" of safety standards at Jensen Farms as the likely sources of the bacterial contamination behind the deaths. But in a report issued this week, congressional investigators found the company that conducted a July safety audit at the farm, Bio Food Safety, gave it near-perfect marks despite finding three "major deficiencies."
In particular, it noted that the company washed its cantaloupe in water that was not treated with chlorine or any other anti-bacterial additive -- a process the FDA said was inconsistent with its recommendations and "a probable cause of the contamination." The inspector did not take points off for the finding, the report states.
"The guidance which Bio Food Safety did not consider in its audit represents the agency's best and most timely advice on how processing should be handled," the House Energy and Commerce Committee concluded in its bipartisan report.
The September outbreak killed 30 people, triggered a miscarriage in one woman and sickened more than 115 others -- the deadliest outbreak of foodborne illness in more than a quarter-century, according to the Centers for Disease Control and Prevention.
Bio Food Safety President Jerry Walzel declined comment on the report Wednesday, citing a pending lawsuit. But he told committee investigators that his company followed FDA regulations, and the agency's guidelines are "opinions."
"We are not supposed to be opinionated on this," the report quotes Walzel. "We are supposed to go by FDA's regulations ... FDA should have mandated that you cannot sell cantaloupes that have not been sanitized."
The report states that in 2010, Walzel recommended Jensen Farms replace a water cooler used to chill the fruit before packaging, citing it as a potential safety "hot spot." The owners replaced the device in 2011, buying equipment that had been used in a potato plant and refitting it.
In October, the FDA found that equipment "did not lend itself to be easily or routinely cleaned and sanitized," allowing dirt to build up. It also criticized Jensen Farms for allowing water to pool on the floor of the packing facility: samples of that water tested positive for the bacteria behind the outbreak.
Jensen Farms had not returned a phone call seeking comment Wednesday afternoon.
The FDA does not regulate private auditors such as Bio Food Safety, a subcontractor for the company Jensen Farms hired to conduct inspections. Under a law passed in 2011, the agency is required to set up an accreditation system and set standards for those firms.