October 19, 2011.- FDA reported this morning that 13 out of 39 environmental samples taken during its initial outbreak “regulatory” investigation at Jensen Farms’ packing house were positive for Listeria monocytogenes. Five out of 10 cantaloupe samples tested by FDA also were positive for outbreak strains of Listeria monocytogenes. City water used to wash the cantaloupes was clean.

Among the 18 positive samples, FDA labs found three of the four different strains of Listeria monocytogenes that have been recovered from outbreak patients, in addition to another strain that has not been recovered from any patients.

FDA and state investigators conducted a “root cause” investigation of Jensen’s operations on September 22-23rd – after the company disassembled and cleaned their equipment and decontaminated the entire packing house. Environmental samples taken during the September 22-23rd investigation were all negative for Listeria monocytogenes, as were samples of cantaloupe taken in the growing fields.

The root cause investigation identified several factors that, according to FDA, “…likely contributed to the introduction, spread and growth of Listeria monocytogenes…”

• There could have been low level sporadic Listeria monocytogenes in the field where the cantaloupe were grown, which could have been introduced into the packing facility
• A truck used to haul culled cantaloupe to a cattle operation was parked adjacent to the packing facility and could have introduced contamination into the facility
• The packing facility’s design allowed water to pool on the floor near equipment and employee walkways;
• The packing facility floor was constructed in a manner that made it difficult to clean
• The packing equipment was not easily cleaned and sanitized; washing and drying equipment used for cantaloupe packing was previously used for postharvest handling of another raw agricultural commodity.
• There was no pre-cooling step to remove field heat from the cantaloupes before cold storage. As the cantaloupes cooled there may have been condensation that promoted the growth of Listeria monocytogenes.

During a morning media teleconference, FDA and Colorado officials were at pains to assure the public that the Jensen Farms packing house was an unusual situation. “There is no reason to believe,” said Sherri McGarry of FDA, “that these practices were representative of the industry.”

FDA has issued a Warning Letter to Jensen Farms, citing “…widespread contamination throughout …” and “…poor sanitary practices in the facility.” The agency has not yet released a copy of Form 483 inspection report, usually handed to the company at the close of an inspection where significant violations have been found.

Jensen Farms has fifteen working days to respond to the Warning Letter with specific steps it has taken to correct the violations.

Yesterday, CDC issued its latest Investigation Update, reporting that this outbreak has claimed 25 lives, caused one miscarriage, and sickened 123 people in 26 states. It will be at least another two weeks, according to CDC, before the agency feels comfortable declaring the outbreak to be at an end.

FDA believes that all of the Jensen Farms cantaloupes have been removed from the marketplace. Nevertheless, juice from cut cantaloupes could have contaminated refrigerator and food preparation surfaces. FDA recommends that consumers who may have purchased the recalled cantaloupes should clean and disinfect their refrigerators and work areas as follows:

1. Wash the inside walls and shelves of the refrigerator, cutting boards and countertops;
2. Sanitize the surfaces with a solution of one tablespoon of chlorine bleach to one gallon of hot water;
3. Dry with a clean cloth or paper towel that has not been previously used; and
4. Wash hands with warm water and soap following the cleaning and sanitizing procedure.

• Dead: 26 (including one stillbirth)
• Infected: 123
• Death rate: 20.3% (21% including the stillbirth)

With more than half of the nation’s states confirming at least one outbreak case of cantaloupe-related listeriosis and a greater than 20% death rate, the public is still in the dark as to which grocery stores sold Jensen Farms cantaloupes, and which restaurants served these contaminated melons.

A few supermarket chains have advised their customers that they carried the recalled cantaloupes. Others have assured their customers that they only carried melons from states other than Colorado (Jensen’s home). Walmart – named by at least two state health departments and by a number of outbreak victims as a vendor of the melons – has been silent. Whole Foods – named by New Mexico as a vendor – also has remained silent.

Outbreaks of listeriosis are slow to emerge, slow to be discovered, and very slow to wind down. The incubation period for this illness can be as long as 70 days – more than two months. This outbreak is no exception. The first confirmed cases developed in late July; the most recent reported onset was at the beginning of October. Additional illnesses are still under investigation in several states.

Even though the recalled cantaloupes are no longer in household refrigerators, the Listeria monocytogenes that they carried may still be lingering. Juice from a cut cantaloupe may have dripped onto a refrigerator shelf and contaminated the refrigerator with Listeria monocytogenes – a microbe that easily grows in the cold.

The Listeria could then cross-contaminate other ready-to-eat items in the refrigerator – perhaps some other fruit, or possibly salad vegetables. Unless a consumer who stored recalled cantaloupe in her refrigerator is careful to clean and decontaminate all surfaces and bins, she and her family will remain at risk.

CDC continues to offer the following suggestions to anyone who may have purchased the recalled cantaloupes:

• Dispose of cantaloupes in a closed plastic bag placed in a sealed trash can. This will prevent people and animals from eating them.
• Wash the inside walls and shelves of the refrigerator, cutting boards and countertops; then sanitize them with a solution of one tablespoon of chlorine bleach to one gallon of hot water;
• Dry with a clean cloth or paper towel that has not been previously used.
• Wipe up spills in the refrigerator immediately and clean the refrigerator regularly.
• Always wash hands with warm water and soap following the cleaning and sanitation process.

For information on which stores may have carried the Jensen Farms cantaloupes, please visit Jensen Farms Cantaloupes – Retail Distribution Information.