Case Studies

How to Thoroughly Decontaminate Your Plant

December 6, 2013
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Introduction
It was the best of contaminations; it was the worst of contaminations. It is the age of new technologies; it was the age of old technologies. Technology keeps evolving. It does this to fill needs. Twenty years ago, there was no need for gaseous microbial decontamination in food facilities, and there was no perceived need for gaseous microbial decontamination in food facilities. However, there’s a need now.

While your company’s current cleaning technologies may be adequate or good, here are two different methods of decontaminating a facility.

Background
The long-established decontamination method is a manual process of spraying and wiping all surfaces. It is a labor-intensive process that requires the user to spray and wipe every surface. With fumigation, some of the steps are the same, but with the last step (the kill step), the agent is in gaseous form, not liquid. So, why use a new method?

All methods can work if the decontamination agent has complete distribution, great penetration, sufficient contact time and is at the proper concentration. Basically, the agent must contact all organisms for a specified amount of time. If it does not contact the organism, then the agent cannot kill it. Keep in mind, decontamination is killing. Nicer words can be used—decontamination, sanitation, sanitization, disinfection, but all of these methods kill organisms.

Safety must always be adhered, which is why many companies go to outside companies or third parties to perform these steps. If an agent is killing organisms, it can harm people. People are just large organisms.

Before decontamination can take place, cleaning must occur. This cleaning step removes bio burden, which affects all decontamination methods. Most agents cannot penetrate soiled loads, which can react or absorb decontamination agents affecting its penetration, making the decontamination ineffective. Therefore, cleaning must be performed prior to any decontamination step. After cleaning is completed, then the decontamination step can occur.

Established method (spray and wipe)
If a facility has a contamination issue, the scope of the work may vary a little, but will generally be as follows. This was paraphrased from a facility that had an urgent need to decontaminate their facility. Steps may vary from facility to facility and company to company.

1. Strategically place HEPA-filtered air scrubbers in the contaminated area to control bio aerosols created during the cleaning process. Check with Environmental Health and Safety (EH&S) for this requirement.

2. Spray and wipe down all surfaces with a detergent that is effective for the typical soiled load. Some detergents can be hazardous, and proper gowning and PPE may be necessary. The user must follow detergent directions since some detergents require dwell times to keep surfaces wet to allow penetrations into soiled loads. If there is refrigeration equipment, the coils and pans should also be cleaned. Gowning rooms should be part of this cleaning process to minimize the risk of reintroduction of organic matter. Compressed air to clean any equipment should NOT be used since it WILL spread contaminants to other areas. Some contaminants can remain airborne for extended time periods, which can cause the contamination to settle to food contact surfaces after the cleaning has occurred.

3. Steam clean equipment and floors to 250oF. Possibly shroud the steam head to control aerosolization. All electrical systems should be protected from steam to prevent failures. If there is refrigeration equipment, the equipment coils and pans should be steamed to 250oF as well. Gowning rooms should be part of this cleaning process to minimize the risk of reintroduction of organic matter. For this to be effective, all surfaces and areas need to be brought up to temperature. If the temperature does not reach certain levels, then the steaming will be ineffective.

4. Spray or fill all floor drains with detergent. Do NOT steam drains. The action of injecting steam down a drain will aerosolize contaminants out of other drains that are connected and cause contaminations to spread to all surfaces and other areas.

5. After cleaning, apply decontamination agent on ALL surfaces with fogging or spray device. All surfaces must be kept wet for time specified on product label. Fogging or spray device should create small particles, which allow them to reach small areas. For manual sprayers, ensure the applicant sprays ALL surface areas. If all surfaces are not wetted and kept wet for the prescribed amount of time, the fogging will be ineffective.

New method (fumigation with chlorine dioxide gas)
A relatively new method for food facility decontamination is using a gas instead of a liquid. The benefit of using a gaseous method is complete coverage of the decontamination agent. With established technology as described above, the user is instrumental in achieving, or NOT achieving, the decontamination. With the new technology, the user is removed from the process, so science or gas laws achieve the decontamination. For any decontamination to be successful, the decontamination agent MUST reach all surfaces for a prescribed amount of time at a specific concentration. All surfaces include nooks and crannies where organisms can hide from liquids. When the decontamination agent is applied, it MUST get into all nooks and crannies. If it does not, the decontamination will NOT be complete and it will be a matter of time until a contamination event occurs. This contamination is a bomb waiting to happen with costly ramifications (recalls, bad publicity, loss of revenue, etc.).

An example of this contamination time bomb was a multi-state outbreak of Salmonella Serotype Tennessee infections associated with peanut butter. The initial contamination was in 2004. During this contamination event, the cleaning procedure was similar to the one described above. Then in 2007, the contamination time bomb exploded with 715 cases in 48 states (CDC MMWR 2007). This contamination time bomb was sitting around the plant for at least 2-3 years waiting to happen. This bomb was created by incomplete decontamination. By fumigating with a true gas, the decontamination is complete and the process does not create the bomb. Gasses follow gas laws such that they get distribution, they get penetration and as long as the concentration is monitored and timed, the contamination time bomb is eliminated.

The process for gas fumigating is similar to the above such that all items must be cleaned (Steps 1 and 2). After cleaning, the gassing can start. The steps involving steaming to 250oF and spraying and wiping (steps 3, 4 and 5) are not necessary, and are instead replaced by the following gassing steps:

3. Gassing. The gassing step involves a few tasks, placing gas generators outside the decontamination space, temporarily installing plastic gas injection tubing, plastic gas sample tubing and fans to aid distribution. At the same time, the space requiring the decontamination requires sealing. This is accomplished with duct tape and plastic. All doorways and entrance/exit ways are simply sealed with the plastic. Plastic commonly acquired from Home Depot, Lowes or Wal-Mart is typically adequate. Processing equipment inside the space should be opened as much as possible to allow gas to penetrate inside. Once the equipment is placed around the facility, the process starts. It starts by raising the relative humidity (RH) to mid-levels or 65%. Higher RH levels can cause condensation. Once the space is pre-conditioned to 65% RH, the gas is injected to a target concentration of 1mg/L (360 ppm). If 1mg/L concentration is reached, then this concentration is held for approximately two hours. This concentration time is equivalent to 720ppm-hrs (360ppm * 2hrs). If the target concentration is not reached, then the exposure time is extended until the concentration time has exceeded the 720ppm-hrs. When all of the CD gas samples are greater than the 720ppm per hours, the CD gas is then removed. This is typically done by exhausting the gas. If the facility does not have an exhaust system, external blowers are used to remove the gas. Once the concentration inside the space is at our below the 8-hour permissible exposure level (PEL) of 0.1ppm, the space can be safely entered. At this point, no further work is required. When the space is turned back over, it can be used immediately and production can start again.

Comparison of methods
When looking at both methods, the beginning steps are the same. Both methods require a thorough cleaning prior to the decontamination step. This cleaning step must be done or the decontamination will not be effective. There is a cost difference between the two methods. The manual method is lower cost due to lower consumable costs, but the time for this process is longer. The time can be shortened by adding more people, but that just adds more cost. The new fumigation method has a higher cost, but is more effective because it easily achieves all four rules for decontamination as mentioned previously. Fumigation also requires technically trained staff and possibly using third-party companies.

With the fogging method and or steaming, particular attention must be paid to electronics. If these items are not in splash-proof boxes, they must be protected. When doing this, these items are then not part of the fogging or steaming and are therefore not decontaminated. These parts must be manually wiped down to ensure decontamination. It is also nearly impossible to bring temperatures up to 250°F. Steel surfaces rapidly dissipate the heat. Concrete surfaces like floors and walls create a huge thermal load that is difficult to heat. Without reaching the required temperatures, the organisms will still remain viable.

Summary
The user must choose between doing the best and doing something to get by. What is at stake is safety, cost, effort, reputation, market share, lives, etc. In the past, the current methods were good enough. They worked—kind of—because they were the best option. But, now there are other options, and these options offer the best outcome for the problem. Fumigation offers the solution to a ticking contamination time bomb. It offers a complete decontamination where one did not exist before. The example for this is that chlorine dioxide gas fumigation was used to eliminate anthrax spores from several facilities around the country. This was the choice fumigant for the federal government. Fumigation with chlorine dioxide gas offers to diffuse the ticking contamination time bomb waiting in every processing or packaging facility.

Fogging is less costly, but less effective. Fumigation is more costly, but more effective. So, what should be done? Should something be done that gets you past the current troubles or should something be done that solves the current troubles? Many times, what is chosen is the easier way and not the most effective way. This mindset is what starts the ticking contamination time bomb. Let’s do what gets us by. Let’s do the simple, cheapest and easiest thing. What needs to be brought up is when this contamination time bomb goes off, people’s lives are at stake.

ClorDiSys Solutions Inc., Lebanon, N.J.

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