Sanitation and cleaning of a food processing facility should be a documented program, following a step-by-step process that has been validated to accomplish stated objectives, utilizing specified chemicals and tools. Sounds easy enough, right? But is it?

First, what are your “stated objectives”? Are you wiping the accumulated dust and debris off the top surface of overhead structures in a food processing area to maintain a sanitary environment as per Good Manufacturing Practices published in the Code of Federal Regulations? Or are you pumping a caustic chemical through the piping of your liquid product handling system to flush out product residue that might support the growth of pathogenic microorganisms? Are you hand-scrubbing pieces of equipment to remove visible soils prior to placing them in a wash basin with hot, circulating chemicals to eliminate any trace of an allergenic product before using that same equipment to process another product that does not contain the same allergenic ingredient? Each of the above scenarios would involve a different set of actions to accomplish and likely require different detergents/cleaning chemicals/solvents and different tools. When it comes to sanitation, one size does not fit all.

Putting Food Safety on the Line
Just as food can be manufactured in a methodical, linear fashion, so can food safety be achieved by following a sequential method—and attention to detail. If deciding your objective(s) for a specific cleaning task is the first step, next you should determine which steps would most effectively allow you to achieve your goals. A good starting point is to learn the steps for disassembling and cleaning the equipment in a processing room by working with your maintenance person both to review the operation manuals for each piece of equipment and to create a step-by-step cleaning program. Often, manufacturers’ machine manuals recommend the type of cleaning chemical that can (or cannot) be used on that equipment.  

The next step in this process is to determine what chemicals will be used for cleaning the equipment (and surrounding areas). Your chemical sales representative should be a good resource for learning the manufacturer’s recommendations on use of each cleaning agent under consideration. Early in my career, I had the good fortune to work with an exceptional sales rep who recommended that I take a food plant sanitarian training course; afterwards, he worked with me to create the Sanitation Standard Operating Procedures (SSOPs) for the entire processing plant. I currently work with an excellent sales manager who is a great resource for keeping current on the newest cleaning products available, and the exact amounts and application rates for each of those chemicals we purchase. I can now write my own SSOPs without any problems.

Both of these individuals worked closely with me to train the sanitation crew to implement and follow the written procedures we created. For successful training, the sanitation crew members must be given a hands-on demonstration of the procedure, with ample time for questions and discussion, be tutored through the actions themselves while being observed and given additional instruction if needed, and then have close supervisor oversight and monitoring of actions until they understand and can follow the procedures they were trained to perform. Having learned from experience that not all chemical sales reps are created equal, I would recommend that if you do not find that yours is sufficiently knowledgeable or willing to assist you in this manner, you might want to try contacting someone at a higher level in that company. Hopefully, they do have this type of resource available to you, if you search for it.

What Is “Clean Enough?”
After working out the details of equipment parts removal and order of removal for cleaning your equipment and which chemicals to use and in what concentration, how do you know when the equipment or room is “clean enough?” Simply put, validation is the process of proving that your written SSOPs, when properly implemented, will actually do the job that was intended to produce the desired result. A good cleaning program removes all visible soils, food buildup and microbial cells. A test result of less than 10 aerobic plate count (APC) or total plate count (TPC) and “negative” for presence of pathogens is what you want to achieve.

For example, to validate the effectiveness of your drain-cleaning procedure, you would have your regular sanitation crew clean the drain using the steps and chemicals specified in the written procedure, and at the conclusion of a “normal” cleaning (before sanitizing), you would swab the drain with sterile microbiological swabs and test for APC or TPC or possibly other specific organisms. During the validation study, you should be taking multiple swabs from many different locations in the drain, especially in hard-to-reach areas such as under the lip or along any point where two surfaces meet to form a line or corner that might be more difficult to clean. Careful description of where each swab touched the drain is imperative to be able to correlate the results back to what part/area was tested at a later date. Taking photos of each swab location that includes a swab or swab container that is already numbered is one simple way to accomplish this.

Validation of a cleaning procedure and process might be something you can do in-house if you have knowledgeable people and a trained microbiologist on your staff, or else very experienced sanitation professionals. Otherwise, I strongly suggest you seek outside assistance with the validation process.

Here is a tip when creating a particular SSOP for the first time: A less-expensive and faster way to find spots that are difficult to clean and might be expected to give a less-than-good result from micro testing would be to use a luminometer and ATP swabs first. The next steps are to reclean and revise the procedure until you can get a zero count with the luminometer and are confident that the cleaning procedure is working as expected before going through the validation exercise with more expensive swabs that have to be sent to a micro lab for testing. Remember, always swab the cleaned area before applying final sanitizer, as the person taking the swabs has touched the area and might have contaminated it, and it will need to have a sanitizer applied before product is run on that equipment. Another reason to wait until after the swabs are taken before applying sanitizer is that some sanitizers cross-react with some of the reagents on certain swabs to give a false-high reading.

If you are validating a cleaning procedure or sanitation program for removal of pathogens and test the cleaned surfaces of food-contact areas for pathogens (such as Salmonella, Escherichia coli 0157:H7 or Listeria monocytogenes), make sure that all food products made on that surface prior to this cleaning are still in your control and on hold status until the testing results are returned to you as negative for all tested pathogens, or else you might find yourself in a recall situation.

What If It Was Not “Clean Enough?”
What happens when the micro lab results come back with higher numbers than you expected or wanted? In this case, your drain was not “clean enough.” There are a number of possible reasons for this:

The first person to question is the one who took the swab samples that returned a bad test result. Is that person properly trained in microbial sample collection technique? Or did she or he perhaps contaminate the swab during the sample collection process? During discussions with quality assurance technicians who swabbed an area that returned a high result, I have occasionally come across some very interesting techniques from people who turned out to have no background or training in aseptic technique. I have compiled a list of things not to do while collecting samples:

•    You should NOT hold the swab in your mouth to free up both hands for removing the drain cover.

•    You DO need to re-cover the swab and protect it from touching other things, even after you used it to swab an area.

•    You should NOT lay the swab on the floor after you sample the area so that you can use both hands to put the cover back onto the drain.

•    It DOES matter if you cough or sneeze onto the swab after you have removed the protective cover, even if by accident.

•    Dropping the swab into a puddle of dirty water on your way back to the lab DOES matter, and it should not be used even if it’s the only one you brought.

The next place you might want to look would be at the personnel doing the cleaning of the area that returned a bad result. You would want to review the written SSOPs with the individual to learn if that person understands what was expected and to ask if she or he might have “improved” on the procedure by leaving out some steps or doing it faster than normal, etc. A common problem I find is that many of the people doing sanitation work do not read or understand English, or else have a deficiency of understanding written instructions, regardless of the language. In this case, more hands-on training is required for that individual; my preference is to photograph every step of the procedure alongside the written SSOPs. Another very effective tool for this training is to show new employees a videotape of the procedure being properly performed.

If your discussion with sanitation and sample-taking personnel has led you to believe that the person performed the procedure and the swab collection and testing were done correctly, then another place to look is at your cleaning chemicals. Are they being used in the proper concentration per manufacturer’s instructions? I have found a situation where the concentration of chemical in the bottle being used was not the same concentration for which the cleaning procedure was written, and no one had noticed because the bottle looked almost exactly the same except for the concentration designation, such as 0.1 N vs. 1.0 N. Is it exactly the same chemical for which the SSOPs were written? Several times, I have found that a company used SSOPs written for one chemical, but later switched to a different chemical supplier and assumed that the new chemical was the same, when in reality, it was being delivered in a weaker concentration. The old SSOPs then no longer applied.

Your cleaning tools and equipment are also places to look. If the process involves a spray- or foam-on application, is the spray syphon system operating properly to pull in the correct amount or is the take-up hose clogged or leaking? Is the water-to-chemical-to-air ratio balanced correctly? Are the sanitation tools properly cleaned at the end of each cleaning shift or have they been left dirty to the point where they now cause contamination rather than remove it?

If all of the previous areas seem to be operating correctly, perhaps the bad micro testing results are because of a surface that is no longer cleanable. If your drain (or other tested area) is older, with scratches, dents and visible cracks or rusted and pitted areas, it may be impossible to clean using the method described in your SSOPs. Each imperfection in the surface to be cleaned, be it a crack or gouge or rubbed-rough area, allows food particles to collect where they cannot be reached by the normal cleaning process. This trapped food allows bacteria to multiply. The narrow inside bottom of the cracks can trap air, which prevents water or cleaning chemicals from actually contacting the bacteria beneath the air trap. It may be possible to clean such a worn or damaged area, but it will require more aggressive cleaning techniques and tools. Specialized cleaning operations such as dry-ice blasting or steam cleaning might get the area “clean enough” but now must be incorporated into your cleaning regime, and the SSOPs must be revised accordingly, for that particular area. More often, a damaged area that repeatedly fails cleaning verification tests will need to be repaired or replaced.

The surface to be cleaned might appear undamaged but fails the micro swab test because it has a biofilm buildup. The biofilm can sometimes be seen as a film that dulls the appearance of what began as a shiny surface, or may appear as a whitish or yellowish residue that can be scraped off the surface using a hard or sharp instrument. How to remove a biofilm depends on its substrate, which is another place where your chemical sales rep should be able to help you. A test kit can be used to determine what type of soil is present on your equipment by simply scraping a small amount of the residue and testing to see what type of chemical will dissolve it. For example, if you process dairy products or ingredients such as liquid egg, your equipment might acquire a white “milk stone” buildup that is formed primarily of calcium carbonate, needing to be acid-cleaned for removal. Other biofilms that form primarily from a burnt-on sugar- or starch-based material or a greasy/fatty/oily material will need a different type of treatment. Sometimes, the film isn’t removed without scrubbing or mechanically scouring the surface clean. Microorganisms protected by a biofilm can be exceptionally persistent and show up over and over again in your micro testing results, indicating that your equipment is not “clean enough.”

Another version of “clean enough” involves allergens. If you process food with one of the major allergens and then process another food on the same equipment that does not have that same allergen listed on the label, you run the risk of allergen material cross-contamination, which can lead to illness or even fatality in allergic individuals. You must validate that the cleaning procedure used between the different types of food can remove all traces of the allergen. An allergen validation is performed in a manner like that described above, but instead of sending the swabs to a micro lab to test for microorganisms, you test the swabs for the target allergen. A number of companies now sell swab kits for the major allergens. Some give a visible color-change reaction to indicate the presence of the allergen, whereas others must be sent for testing to confirm the presence (or absence) of the allergen. Many third-party audits require that an enzyme-linked immunosorbent assay-based test be used to confirm the absence of allergens.

Keep in mind that no matter how much money you paid a testing lab for your validation study results, that study and the results are valid only for the exact procedures and chemical cleaning agents specified in your SSOPs. If you change chemical suppliers, you must redo the validation study using your current chemicals. Some audit companies now request that you redo the validation study annually to ensure that the cleaning process still works. Over a year’s time, surfaces can become damaged or biofilms can accumulate or the surfaces can be etched by acid sanitizers, and the cleaning procedures may no longer be sufficient. Anything that removes the hard, shiny surface the equipment once had can cause it to become more and more difficult to bring back to a “clean enough” state.

Restoring “Clean Enough”
An alternative being used by many smaller companies is to hire a contract sanitation company to bring in a crew of professional sanitarians, rather than having operations employees do the cleaning. A good, competent sanitation professional does not just walk in off the street; this individual must be sufficiently strong enough to pull around heavy hoses and sanitation equipment, able to lift and move heavy machine parts, have the stamina to physically scrub food residue off equipment and lungs robust enough to work in a hot, steamy environment that sometimes involves strong chemical fumes and the endurance to do all of this wearing heavy boots and protective clothing. To be good at his job, this person also needs to have meticulous attention to detail and be self-motivated to inspect his work and reclean an area that isn’t right the first time. He must also be willing to work third shift and/or weekends. The sanitation employee described above only becomes competent with experience; after getting experience and being good at their job, these people are not minimum-wage employees. That is a major reason why many smaller food processing companies are looking to contract cleaning as a resource, because they do not feel that they can afford to pay the wages needed for retaining an entire crew of good sanitarians full time. Others have been able to cut costs based on longer production runs that require the system to be completely cleaned only at periodic intervals, thus allowing the use of a contract cleaning service rather than full-time sanitation employees. Some have done the micro testing and used a history of no problems to justify the risk of running longer production lots with only minimal cleaning during the week, and then having a complete breakdown and cleaning of equipment only on the weekends.

Keep in mind that the company making the food is still the one responsible for ensuring that the entire facility stays in a sanitary condition and that the facility and all the equipment are “clean enough” to produce safe food. “Trust but verify” and make sure you have the documentation to show that your equipment is indeed “clean enough.”

If It’s Not Enough
Ultimately, you define what is “clean enough,” sometimes with direction from regulatory officials or third-party auditors. Then it is the production facility management’s responsibility to ensure that all SSOPs are implemented and that the results are properly documented.

This system works well until something goes seriously wrong. Typically, a sanitation failure comes to light only when it has progressed to the point of grossly contaminating product. For example, one night of forgetting to remove the belt off a product-contact conveyor to clean the underside might not cause a major problem by the time the system starts up again the next morning, but an employee deciding to bypass the SSOPs and failing to remove the belt night after night would allow residue to accumulate to the point where it contaminates most if not all of the product moving along the top side of the same belt. In this last example, a poor decision made by a sanitation employee of it’s “clean enough” after just spraying water on the top side of the belt, a supervisor who did not go out to inspect all of the equipment to see if things were cleaned properly and no quality assurance person checking to see if everything was really clean prior to start, over an extended time, led to the company having to recall product containing L. monocytogenes with an associated cost of millions of dollars and loss of an entire product line.

I cannot stress strongly enough that plant management must always be diligent in checking to see that all sanitation procedures are properly implemented all of the time. Unannounced inspections of equipment and facilities should be performed by more than one member of management, at irregular intervals and unexpected times, to ensure that the sanitation program stays compliant with those policies and procedures that were validated to get the facility “clean enough.” None of us wants to end up in court trying to explain why we did not use due diligence to make sure that our consumers never became ill with a foodborne illness!   

Donna F. Schaffner, M.Sc., is the associate director of food safety, QA & training at Rutgers University Food Innovation Center.