Less is more. That’s the general rule of thumb when it comes to using water to clean in a commercial bakery, and here’s why.

“When I don't have to do the water treatment, I meet my sustainability goals, and I don't put my employees at much risk because when I use water, I’m going to use chemical cleaners, and that puts people at risk,” explained Karl Thorson, global food safety and sanitation manager, General Mills, Minneapolis. “With water, you have to deal with chemicals and a greater level of equipment disassembly, and usually that requires a higher skill level for people to do those kinds of tasks.”

For years, Mr. Thorson has spearheaded the concept of a “war on water” for sanitation in bakeries. Actually, the “war” is more of an order of preference for cleaning based on total cost, time, risk and a host of other factors.

In General Mills’ nine-step ranking of cleaning, the most affordable and efficient method is, logically, no cleaning required. That’s followed by using a purging process, dry cleaning and dry cleaning with chemicals. Using clean-in-place and controlled wet cleaning fall in the middle. The most expensive and aggressive methods are assisted cleaning systems, controlled wet cleaning in place and, finally, flood cleaning.

“We've gotten great support across the entire industry,” Mr. Thorson said. “In general, that hierarchy of cleaning methods that we've published still holds true.”

He added that following the ranking of cleaning methods provides the fuel for driving significant improvements not only in food safety but also efficiencies and capacity in the future.

Both wet and dry cleaning can be effective and efficient if the equipment has incorporated hygienic design principles, noted Nathan Mirdamadi, senior food safety specialist, Commercial Food Sanitation, an Intralox company.

In general, wet cleaning is acceptable if it’s done well and if there is a kill step where products reach a specific temperature in an oven or fryer that eliminates harmful bacteria and reduces microbials to safe levels.

“Failing to clean well when using wet techniques will lead to environmental pathogen challenges,” he added. “Dry cleaning after the kill step is nearly always preferred, but it does require the use of a different and unique set of tools which most are unfamiliar with using.”

If wet cleaning is used but the equipment and environment has hygienic design flaws, the moisture, soil and niches will lead to environmental pathogen control challenges, even on production lines with a kill step.

“When a soil has a low-water activity, dry cleaning should always be the preference,” Mr. Mirdamadi advised. “Even for allergen removal after the oven, the introduction of water should be debated because of the environmental pathogen risk that using water causes.”

Bret Zaher, manager at AIB International, pointed out that dry cleaning is effective during quick changeovers, but it is often insufficient for deep cleaning.

“Although dry cleaning removes much of the dry residue, it does not always remove it all, which could result in allergen cross-contact issues and/or loss of finished product claim status like for organic or Kosher products,” he said. “An improper dry cleaning can also leave behind other non-allergen ingredients that could also result in customer quality complaints.”

He added wet cleaning is often necessary to keep production running.

“Many times, product buildup gets so sticky that it jams conveyor rollers or even prevents the work-in-process product from properly continuing through the production process,” Mr. Zaher explained. “The challenge with wet cleaning is that it takes additional time for proper pre-cleaning preparations, equipment teardown and set-up, as well as drying time.”

When choosing a cleaning method, sanitation crews need to consider such factors as what could happen to certain product contact surfaces when they get wet.

Some concerns include mold growth, warping of the equipment or product residue getting stuck to the surface.

“Bakeries using cloth and felt conveyors and wooden baking boards should avoid getting them wet,” Mr. Zaher said. “The same goes for the wrapping department, in which water should not be added to bread slicers so they don’t warp, rust or accumulate product residue. 

Wet cleaning is normally used when removing sticky ingredients like fillings or for allergen changeovers. Most bakeries use both types of cleaning, depending on ingredient, dough or other buildup debris. 

Mr. Zaher recommended dry cleaning for daily housekeeping and maintaining a sanitary condition to avoid spillage and buildup that can result in potential food safety issues. 

“Usually, wet cleaning takes place at the mixing, dough molding and proofing areas, and dry cleaning is used everywhere else,” Mr. Zaher explained. “However, dry cleaning can also be used in these areas if it is a simple color change or adding a non-allergen or non-identity preserved ingredient.”

Additionally, he added, wet cleaning often occurs on product scales and conveyors prior to packaging to remove residue from previous product runs. 

“Discuss the proper cleaning and sanitizing chemicals with your chemical provider and use the right concentrations during your wet cleanings,” he said.

This article is an excerpt from the October 2023 issue of Baking & Snack. To read the entire feature on Sanitation, click here.