“Water poses a significant food safety risk in dry and low moisture food processing environments,” says Nathan Mirdamadi, a Senior Food Safety Specialist with Commercial Food Sanitation. That makes cleaning and sanitizing these areas challenging, particularly considering the detrimental effects of microorganism growth on human health. 

Microorganisms need moisture, the right temperature, and just a little bit of time to grow. Some organisms such as yeasts and molds and microorganisms such as Salmonella are capable of surviving for long periods of time in dry environments and just a little moisture can be a tremendous catalyst. once these pathogens begin to spread they wreak havoc on food production facilities, causing production shutdowns, recalls and foodborne illness outbreaks. It wasn’t until the late 1990s, that Salmonella was first identified in dry cereal, and the risk of microbial contamination in dry and low moisture food products was even recognized. Today, regardless of the processing environment, it is well understood that moisture, microbial growth and migration must be controlled. 

Moisture can enter dry food processing environments in a multitude of ways. Humidity and condensation are common culprits when adequate HVAC systems are not in place. Employees may also track water residue from wet to dry areas as they move about if donning and doffing controls are not in place. The misapplication of water during cleaning and sanitizing of dry environments is an obvious manner in which water can be introduced. Good Manufacturing Practice (GMP) per FDA’s 21 CFR 117 “Current Good Manufacturing Practice, Hazard Analysis, and Risk based Preventive Controls for Human Food” can help to identify hazards for which prevention and correction strategies must be developed. 

But what about the risk of microbial spread encouraged by the very products intended to mitigate them? Effective cleaning and sanitizing in dry environments is a great concern, particularly considering most cleaning and sanitizing products on the market today are composed of primarily water. 

Whether cleaning food contact surfaces or flooring, in both wet and dry environments, pathogens like to hide in plain sight, in those pits and cracks that are difficult to see, clean and inspect. Moisture can encourage their adhesion to surfaces and microbial growth. In dry food processing environments the problem is particularly compounded as the dry material mixes with moisture to form a paste. “If you get water into a spice line it is a nightmare,” says Jared Torgeson, Business Development Manager at Pureline. Because of water’s risk, many food processors, regardless of the food processing environment’s tolerance for moisture, are turning to dry cleaning and sanitation practices for routine use.

“I think in general all segments of the food industry have begun to appreciate the importance of controlling moisture as an important aspect of controlling microorganism growth,” says Mirdamadi. It’s important to note that without a clean environment, sanitizing will be ineffective.

Cleaning in a dry food processing environment

In an ideal world, all equipment and facilities should be cleaned in the same manner. But, given the complexity of equipment design, facility layouts and surfaces and opportunity for cross contamination, particularly between wet and dry areas, robust cleaning protocols must be implemented specific to the environment.

Experts recommend always cleaning from the top down in dry environments using brushes and scrapers that loosen soils. Next, remove the loosened soils with a vacuum fitted with a HEPA filter or very controlled compressed air. Compressed air is typically a last resort because users must be cautious that the air isn’t merely blowing soil, microorganisms, and allergens from one area to the next. After all visible dirt has been removed, FDA-approved sanitizer can be used to wipe away any remaining residues. 

once equipment is clean, perform a visual inspection, swab it and re-clean as necessary. once cleaning is verified, it is time to sanitize. 

Dry sanitation

In the U.S., dry sanitizing of food contact surfaces requires an EPA registered food contact surface sanitizer but one that doesn’t introduce unnecessary moisture. If the sanitizer is approved, no rinse is required.

“The real challenge,” says Mirdamadi, of dry and low moisture environments “is sanitizing efficiently and effectively.” In wet environments the use of foamers can saturate surfaces, for instance, which is effective and thorough. But in dry environments, the available sanitizing methods are more arduous. “You can’t put dry sanitation solutions into a foamer,” he says of the need to eliminate the introduction of water.

In some instances a more thorough disinfection is required, such as a facility restoration after a known contamination event. In these instances, a gas solution that is able to permeate the entire room, reaching all surface areas, even those the eye can’t readily see, can be most effective. Chlorine dioxide generated gas, for example, resets and decontaminates the environment. “It permeates every nook,” adds Torgeson, “and provides peace of mind.” Generated onsite, use of chlorine dioxide gas is digitally monitored and logged to assure target concentrations are achieved over an eight-hour treatment. It can be used routinely or as a facility reset.

Addressing problem soils

Sometimes, soil can be particularly difficult to remove with only dry cleaning techniques. If water or steam is required to eliminate debris on equipment used in a dry processing environment it is best to disassemble and remove the necessary parts to a washroom wher traditional wet cleaning techniques can be used. Before returning the newly cleaned and sanitized equipment back to the food processing environment everything must be completely dry to avoid encouraging microbial growth. 

In these cases in dry operations and after wet cleaning and sanitizing, it is a good practice to resanitize equipment once reassembled and in place using dry techniques. “During reassembling there is a risk of recontamination,” Mirdamadi suggests. “A second sanitation can be a valuable extra effort in these cases.”

Dry food processing environments have particularly unique needs when it comes to cleaning and sanitizing. “One of the benefits of chlorine dioxide gas is that it can be 100% effective,” says Mirdamadi. 

When every decision impacts safety, you’ll want to get it right.