Many successful truck wash operations utilize an internal audit system where someone is responsible for monitoring processes as trucks and trailers move through the wash, according to Erin Kettelkamp, DVM, with the Swine Vet Center.

What should these audits or assessments include? Kettelkamp uses an evaluation form that helps her gain a good understanding of the day-to-day practices at a truck wash. Her goal is to understand the flow of traffic throughout the day, how many trailers are getting washed each day, whose trailers are getting washed, and the logistics associated with individual truck movement. From there, she wants to understand the company's expectations for washing standard operating procedures and whether the behaviors – what is actually being done in the truck wash – match the written SOPs.

"If the goal at the end of the day is to have a very clean trailer, it's important that we're measuring and assessing that process," Kettelkamp said, noting that inspecting a trailer while it's still in the wash bay helps ensure the wash crew has gotten into the hard-to-reach areas, and if necessary, allows them to rewash missed areas without having to pull a trailer back into the wash bay.

She said some of those hard-to-reach areas include the ceilings in the lower levels where there can be spray residues, along the support rails where dust can accumulate, and behind gates and hinge points. Kettelkamp said in trailers with multiple decks, the ramps don't always get pulled out fully during the wash process so shavings and other materials may hide there and re-contaminate the trailer.

Depending on the configuration of a trailer, the nose of the trailer may have different angles and supports that a washer – normally facing the front of the trailer while washing – may miss because they may not turn around and find the non-standard hiding spots.

Kettelkamp said the focus of the wash crew should be to remove all organic material in order to implement an effective wash. "First and foremost, we have to do a really good job with the initial power wash. We can layer on all the disinfectant we want, but if we're not getting the initial wash done right, then disinfectant and all those other steps really aren't going to help us any," she said.

For the disinfectant step, she said a variety of disinfectants are used throughout the swine industry, and as long as they're verified to be efficacious against all of the major pathogens, they tend to do a good job if the trailer has been thoroughly power-washed first.

This includes the outside of the trailer, especially the wheels, wheel wells and belly of the trailer, which should all get a good full rinse. She suggested that during the winter, if the snow and slush is not getting cleaned off the outside of the trailer, and if trailers are being pulled out of wash bays that haven't had time for the ice to melt off, the wash crew is probably not doing a very complete job.

Kettelkamp said a best practice should be to have trailers washed between each use, but from a logistics standpoint, the industry hasn't been able to move in the direction of fully washing between every downstream trailer movement. She said a general expectation would be that trailers coming into contact with a sow farm or other high health site should be washed, cleaned and disinfected before every use.

Automation
Kettelkamp noted that there's been some discussion about automated truck wash bays for the cleaning of feed trucks and other vehicles that may be entering pig production sites. These systems may help decontaminate wheels, wheel wells and the bellies of vehicles that do not come in direct contact with animals. The poultry industry has installed some of these automated systems, but Kettelkamp is not aware of any in use in the swine industry.

Otherwise, washing trailers is back-breaking work, especially when scraping and washing triple- or quadruple- deck trailers, so some type of automation could help in those situations.

Baked trailers
According to Kettelkamp, some swine companies have been "baking" trailers as an extra step in the process. To do so, the wash bay or other room is heated until the surface of the trailer reaches a temperature of 160°F for at least 10–15 minutes to deactivate viruses such as porcine reproductive and respiratory syndrome virus and porcine epidemic disease virus.

She noted that the process can also be effective if the trailer is heated to a lower temperature that is held for a longer duration to dry out and bake the trailer.

A full cycle time for a truck to enter a bay and heat the room long enough for the surface of the trailer to reach 160°F for 15 minutes can take more than 1 hour, depending on the external weather conditions, Kettelkamp said.

Surrounding truck wash biosecurity
Beyond looking at the cleaning practices of trucks and trailers, Kettelkamp said it is a good idea to look at the biosecurity of foot traffic and vehicle traffic around a truck wash.

Wash facilities should be set up in a linear arrangement or potentially in a circle, where dirty trucks or vehicles may enter on one side or through one driveway and nothing gets past a line until it goes through the wash and disinfection process before it can be on a designated clean side of the wash.

That way, she explained, cross traffic between vehicle employees and/or maintenance trucks on the site is minimized. There should be clear lines of demarcation of "this is dirty" versus "this is clean" and our washes should be managed that way, she said.

The site for the truck wash also should be carefully chosen so clean vehicles are parked upslope from unwashed trailers; in the case of rainfall, runoff from dirty trailers should not flow to where clean trailers are parked, exposing them to recontamination, Kettelkamp said.

"We should have the same thought processes and practices for entering a truck wash as we do for entering a sow farm. How do we minimize cross contamination within our buildings or setup and how do we keep trailers clean and minimize foot traffic in and out? What are our designated dirty areas? What are designated clean zones for foot traffic on a wash?" she said. "We know we're dealing with a lot of fecal material, but if we're tracking it all around the site and potentially re-contaminating other areas, including trailers that were initially clean, we've got to think of a better way to mitigate that risk."

Developing truck wash SOPs, validating, and assessing how well those SOPs are employed and considering how vehicles and personnel move around a truck wash are all key aspects that will help improve site biosecurity.

Tim Lundeen is chief editor at Tarn Wordsmithing, where he blogs about innovations in animal agricultural research and does freelance content development projects. He previously spent 20-plus years as staff editor at Feedstuffs. He can be reached here via email.