Swine veterinarian Peter Provis challenges the pressure washer's mantra: “If it looks clean, it's clean enough.”
Looking clean and “being” clean are not the same thing, emphasizes the consulting veterinarian and partner in the nine-member Sheridan, Heuser, Provis Swine Health Services clinic of Steinbach, Manitoba.
From the trigger end of a power-washing wand, appearances can be very deceptive, Provis says. “Maybe farrowing crates aren't as clean as we think. The clinical severity of diarrhea seems to lessen when we focus on getting rid of biofilm. We think our disease complexes are simply hunkering down in the biofilm. Disinfectants really aren't getting the job done.”
“Biofilm is the shag carpet of the bacterial world,” Provis says. “It is very common, very widespread, resistant to cleaning and reasonably invisible.
“It is a mixed layer of hard water deposits, mineral scale, soap, organic matter, bacteria, viruses and molds. It forms a hard-to-remove layer on surfaces in farrowing rooms, from floor bolts to farrowing crates to ventilation ducts,” he continues.
“It can't be just power-washed off. We recommend using acid cleaners, acid detergents and physical cleaning with a power brush or old-fashioned scrub brush and pail to dissolve the biofilm.”
Biofilm can be seen on the white, plastic material used for partitions or flooring. It is part of the brown or gray mineral scale that builds up on this plastic. However, biofilm can be present even when the plastic looks white, long before a color change is visible, Provis says.
Effective sanitation to prevent disease is costly, but not as costly as treatment.
Provis lists the key components of sanitation as washing, cleaning, disinfecting, drying and monitoring. Whether done well or poorly, sanitation carries certain costs.
“Many producers wash without soap. That increases the amount of time it takes to wash, increases the amount of water it takes and ultimately, increases costs,” he explains. “Using detergent will save you money, save you time and do a better job.”
Provis lists these basic costs, assuming a crate is washed and cleaned about 16 times a year (CAN$):
| Labor | $30 |
| Manure removal | $4 |
| Acid degreaser | $4 |
| Disinfectant | $8 |
The $46 per-crate total is equivalent to about $34.50 U.S. dollars.
Attacking dirt and biofilm effectively is a multi-step procedure, Provis explains.
He rates washing as half the job in a sanitation program. Cleaning is about 49%. Disinfecting is what's left.
Washing gets rid of the manure; cleaning gets rid of the biofilm. “People often think they've done a good job when the manure is gone,” he says. “They can't see the biofilm still clinging to the surface.”
Overlooking some areas during a washing procedure is a common mistake, not unlike brushing your teeth without flossing. Thorough washing really takes the kind of care that a dental hygienist uses in flossing teeth. “You floss to the corners, or it's just not clean,” Provis says.
Flossing goes beyond sow feeders and creep feeders, he says. It includes nipples, crush bars, ventilation ducts and floor bolts.
Floor bolts can only be cleaned with a brush. No amount of water pressure and heat will take out the hidden bacteria.
Similarly, bacteria slip into the ventilation system. Once the ducts of a ventilation system are taken apart, they can be washed easily with a pressure washer.
If you were to study bacteria under an electron microscope, you would see why bacteria survive so well, Provis explains. Some give the appearance of spinning a cocoon around themselves so they can stick to almost anything. They'll stick in microscopic cracks on surfaces that look hard and very smooth.
“One of the least important jobs is disinfecting,” he adds. “That's the final step, but disinfectant can't penetrate manure and biofilm. It only works with a clean surface.”
Step one — Wash the room and crate properly. “If you can't wash the manure out of farrowing crates and out of your barn, you're not going to be able to disinfect it, no matter what.”
The effectiveness of disinfectants in the presence of manure has been studied. “Many of them don't work well, or have dramatically reduced activity in the presence of any manure or bio-matter,” he says.
For starters, set the water temperature to 200° F. and pressure to 2,000 psi (pounds/sq. in.). Then, pay attention to detail. Simply turning up the water pressure or temperature won't help a bit.
Step two — After the manure is gone and surfaces look clean, attach a foam gun to the end of the pressure washer. Advantages of foam include:
Foam clings to the surface, increasing contact time.
Foam has uniform product concentration.
Foam reaches into inaccessible surfaces, such as under slotted floors.
Foam is more visible, so there's no doubt about what's been covered or missed.
“If you spray on a thick, clinging blanket of foam that contains your degreaser or disinfectant, we believe you get longer, better coverage, and better concentration of your product right at the site you need to disinfect.”
Step three — Apply an acid cleaner to cut through the biofilm, destroying the bacteria and killing mold as it takes off the scale. Follow label directions to ensure proper concentrations are used.
Several good commercial acid cleaners are available. Ask your veterinarian or supplier for a recommendation.
Step four — Let the room dry completely before restocking. Once a surface has been washed, cleaned and disinfected, it may still support virus reproduction while it is wet. If given an hour to set completely dry, the last virus inhabitants will no longer be a threat to incoming stock.
He stresses, “If you do everything right except dry the crates, you'll still get transmission of virus. You must let the crate and the room dry completely to effectively kill what you need to kill.”