Bacteria found in even the cleanest food tanks

April 5, 2006
Even the best foodgrade cleaning system available today will not fully eliminate potentially harmful bacteria from a tank trailer, according to data collected for a University of Florida research project that is being funded by the federal government and various food industry associations.

Even the best foodgrade cleaning system available today will not fully eliminate potentially harmful bacteria from a tank trailer, according to data collected for a University of Florida research project that is being funded by the federal government and various food industry associations.

However, proper cleaning processes can reduce the presence of microorganisms to a level where they appear to pose little or no health risk.

Preliminary results of the research project were presented April 4 during the annual National Tank Truck Carriers Tank Cleaning Council Seminar in Las Vegas NV.

Paul Winniczuk, a University of Florida graduate student using data from the research project in his doctoral thesis, said that wash racks need to develop very specific cleaning recipes for each food product cleaned at the rack. Tank trailers need to be cleaned at the correct with water and other solutions at the correct temperature and correct amount of time. He criticized the use of 180 F water, saying it will bake food residue onto the tank wall. “You can clean most food products with 140 F water,” he said. “You just have to run the wash cycle for at least 15 minutes.”

Soap concentration should be just right, and sanitizer should be used. The sanitizer cycle should last at least two minutes. Winniczuk pointed out that even good quality water from a municipal water plant contains microorganisms, and they will begin to grow in a clean tank with in 24 hours if a sanitizer is not used. Contamination also can come from gasket and seals with even the most minute cracks and crevices. Disassembled valve parts can become contaminated if workers set them on fenders, bumpers, and other areas that are not clean. “In some cases, the cleaning process is putting bacteria back into the freshly cleaned tank trailer,” Winniczuk.

What are the microorganisms being found? The University of Florida study is looking at five key organisms that pose a significant health threat: Coliform, fecal coliform, E Coli, Salmonella, and Listeria.