With applications across the food processing industry, the use of chlorine dioxide gas is relatively new. But, says Nathan Mirdamadi, a food safety consultant with Commercial Food Sanitation. “I wish more people knew about it.”

Food processing environments are inherently challenging. With bacteria doubling in wet environments every 15 to 30 minutes, each decision is potentially life threatening. Even small areas of contamination from organic matter such as Listeria can grow to be a significant problem. When a single piece of food processing equipment can introduce microorganisms that kill, staying ahead of food safety is a must.

Whether post new-construction, equipment installation or after facility upgrades, removing risks prior to starting or restarting food production lines can make or break a facility’s hygienic environment. Those risks are many and varied considering the number of people entering the facility, dust and debris during construction, equipment changeover and set up, and raw materials moving in and out during the equipment’s acceptance and testing phase.

“When the facility is a construction site, Good Manufacturing Practices (GMPs) are not important,” says Nathan Mirdamadi, a food safety consultant with Commercial Food Sanitation. “But, when it is time for that processing equipment to come online and food production to begin, GMPs are absolutely necessary to prevent contamination from both foreign materials and microorganisms.” He likens the post-construction decision to clean and sanitize, or decontaminate as he terms it, as drawing a risk prevention proverbial line inside a facility at the close of any capital project. 

For an increasing number of food processing facilities, that proverbial line is drawn with chlorine dioxide gas following a thorough facility clean.

“I wish more people knew about it,” says Mirdamadi of chlorine dioxide gas. Mirdamadi helps clients develop safety plans during their facility’s design and build phases as well as post construction. “As a consultant, I am usually called in after a problem has been identified, and chlorine dioxide gas is a great tool in the toolbox.”

Choosing an effective sanitizer

The decision of which sanitizer to use is an integral part of a facility’s GMPs but they are only effective when preceded by a thorough clean. Sanitizing the surface of a spec of dirt won’t provide protection from the organisms within it. Once that surface is penetrated, whatever is underneath will spread.  

While cleaners are designed to be washed away, an appropriately chosen and used sanitizer will kill any remaining bacteria. A sanitizer should be appropriate for the facility’s conditions, effective for the microbial loads being targeted, and robust enough to be effective across a variety of conditions, including changeovers within the production facility.

Chlorine dioxide gas

While chlorine dioxide gas is highly effective, it is important to remember that it should only be used by either qualified experts or food processing facility staff who are trained to properly use it. “It is a dangerous gas,” says Mirdamadi, “though everything in a food processing environment carries risk. Chlorine dioxide gas can be safely used with the right precautions.” 

He notes in his experience that risk tolerance is often the deciding factor in whether a company  chooses to decontaminate by bringing in experts such as those at Pureline or train their own staff to perform sanitization. “A lot of companies will do their own treatments after seeing Pureline do it on several occasions,” he says. “Others, at the end of the day, don’t want that risk and choose to continue bringing in the experts.”

An important consideration when planning to use chlorine dioxide gas is air movement, not just post sanitizing when expelling the gas, but also during the treatment itself. Chlorine dioxide gas  is only able to kill what it comes into contact with. “Pureline will bring in fans to keep air moving and maintain an equal distribution of gas in the space.” Mirdamadi also recommends thinking in advance about how to evacuate the gas once the treatment is complete. Scrubbers are one option or the gas can also escape through HVAC systems that pull in fresh air. 

Facility and equipment design 

Sometimes facility design can make cleaning and sanitizing more of a challenge. It’s always good to proactively work with a food safety consultant in advance to ensure risks such as floor drains and HVAC placement are appropriately addressed before the concrete is poured.

Equipment design can also make cleaning and sanitizing more challenging. Meat slicers and spiral freezers are two such examples. Those working in micro-sensitive environments will want to sanitize more frequently. Sometimes the environment of the food processing facility is the driver, as with bakery and snack production where the introduction of water should be avoided. Often the purchase of used equipment prompts the need for facility decontamination, such was the case of a client Mirdamadi’s who rented a third-party warehouse so that they could use chlorine gas to decontaminate an entire line of used food processing equipment prior to installation in their facility.

Equipment is costly so facilities do everything possible to ensure a long and productive lifespan. Today’s standards of sanitary equipment design weren’t as readily used or even known in years past so many older pieces of equipment have collection points where liquids and product can build up. Think bolts, brackets, screws and junction boxes instead of continuously welded joints.

Whatever the food safety challenge, Mirdamadi recommends decontamination as close to starting or restarting food production line as possible. The risk of microbiological contamination restarts as soon as the sanitizing step is finished. Once any sanitizer, including chlorine dioxide gas, is released or scrubbed from the environment, the microorganism clock begins ticking.

“I’m a stickler at all times,” he says of using post-decontaminant spore indicator kits to verify that the treatment concentrations were effective enough to kill the spores. “Food safety people see the world differently.”

Sanitizing is the last line of defense in food safety. Proactively seeking expert advice for effective solutions are the keys to getting it right. Food safety experts such as those at Pureline can help.

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