Food Protection Connection: Dirty Little Secrets - What Your Equipment Won’t Tell You
(reprinted from Dietary Manager, February 2008)
Each Food Protection Connection column is approved for 1 CPE hour (level 1) for RDs and DTRs.
When it comes to cleaning and sanitizing, we work in a vacuum. We don’t see the pathogens on food contact surfaces, yet every day we take steps to destroy them. If your food equipment could talk, what would it really tell you about dirt and germs? This column explores some of these “dirty little secrets”. Let’s start with dirt or more technically, “soil” that resides on the surfaces of pots and pans, dishes, slicers, mixers, and the like…
Secret #1. You can’t always see soil.
We think of soil as the brown stuff in the garden or under the lawn, but some soil is not visible to the human eye. Soil can vary in composition, containing fats, proteins, carbohydrates, minerals, sand, fine metal particles, or charred or carbonized residue from cooking—and combinations of these. Each type of soil responds to detergents differently. For example, many carbohydrates are soluble in water, while fats require an emulsifier, and proteins require alkaline cleansers for removal. Enzymes are used as ingredients in some cleaners today; these are specialized proteins that break down organic substances. Stubborn mineral build-up often calls for acid cleaners.
Secret #2. Bacteria form resistant biofilms on food contact surfaces.
A biofilm is a mass of bacteria that have formed their own sort of “glue” and constructed a hazardous film over a surface—even on stainless steel. The process begins when a few bacteria attach to a surface. As bacteria multiply and a colony develops, the bacteria produce chemical substances that build a protective matrix. The matrix is tough and hard to permeate. Sanitizers can “slide” right over it without harming the bacteria within. In some cases, a chunk of the biofilm can break off, releasing live bacterial cultures. Besides bacteria, other pathogens such as fungi can also form biofilms. Biofilms are not limited to the foodservice environment. They can also form in the body (e.g., on teeth as dental plaque), in healthcare environments, in plumbing systems, and in manufacturing plants. While research focuses on techniques for preventing and destroying biofilms, experts suggest that scrupulous attention to conventional cleaning and sanitizing techniques in food service is our best ammunition against the dangers. Diligence in the cleaning process is especially critical, because this helps remove the biofilm before sanitizing. If a biofilm persists, even a chemical sanitizing agent may not be effective against the protective barrier of a biofilm.
Secret #3. Damaged food contact surfaces may not be cleanable.
While stainless steel is very tough, withstanding acid, salts, and corrosive agents, other surfaces are not. Aluminum, for instance, is readily damaged by food acids and by alkaline cleaners. When a surface becomes corroded, pitted, cracked, or roughened, cleaning (and sanitizing) become less effective. Plastics are also subject to damage. Even polished stainless steel, when subjected to abuse (e.g., improper cleaning) can have its smooth surfaces marred. The problem with any surface damage is that sanitizing agents can’t reach the germs to do their job. Tiny crevices serve as hiding places. It’s important to select high quality equipment, and to inspect equipment regularly. If surfaces are damaged, discard and replace equipment.
Secret #4. An unclean surface can’t be sanitized.
Much as a rough surface can’t be cleaned, a surface containing soil deposits can’t be sanitized. Soil deposits render a surface uneven as well, making it impossible for sanitizing agents to make solid contact. In addition, some soils chemically inactivate a sanitizer. Among the choices of agents, quaternary ammonium compounds (quats) are least sensitive to small soil deposits, but as there is no way to measure their effectiveness in the kitchen, it’s best to aim for perfection.
Secret #5. With chemical sanitizers, more is not better.
Conscientious foodservice employees are often tempted to boost concentrations of sanitizing agents when mixing a solution, with the thought that a little extra will be more effective. In fact, beyond standard concentrations, chemical sanitizers are no more effective, and can damage food contact surfaces. However, length of contact time does have an impact.
Secret #6. With chemical sanitizers, very hot water is not better either.
Our instincts tell us the hotter the water, the better we can clean and sanitize equipment. But that’s not true. Yes, for heat sanitization, temperature is everything. For chemicals, though, water that is too hot can make chemicals vaporize, weakening solutions. This is most true for iodine and chlorine solutions. On the other hand, using cold water (below room temperature), makes chlorine compounds less effective. Corrosion is also a concern. When dissolved in excessively hot water, quats are more likely to cause corrosion, especially on brass and copper. Chlorine solutions likewise become more corrosive as water temperature rises. Remember that heat is not necessary for chemical sanitization; chemicals are an alternative to high temperatures, not an add-on. To be safe, review the temperature guidelines for the product you use.
Secret #7. Water quality affects how well sanitizers work.
Factors such as pH (alkalinity or acidity), as well as water hardness, can have dramatic impacts. Chlorine sanitizers, for example, generally don’t work when pH reaches 7.5 (alkaline), or when it drops to 5.0 (acid). Detergent residue is notorious for crippling certain chemicals, so thorough rinsing after washing is imperative. For detailed specifications, read product details and talk to your product representative.
Secret #8. Misusing detergent can make equipment dirtier.
Using the wrong detergent can leave equipment with even more residue, compounding problems. As an example, using an acid cleaner to remove protein build-up makes the protein precipitate, and basically sets the soil. Using the wrong product or overapplying detergent may also damage surfaces, contributing to Secret #3 issues above.
Arizona Dept. of Health Services. Food Equipment Cleaning and Sanitizing:
Secret #9. Just because products are approved for use in food service doesn’t mean they are harmless.
Many kitchen chemicals can cause serious injury through skin contact, vapor inhalation, and more. Employee safety measures are essential. Are your work teams trained in safe use of cleaning and sanitizing products? Do they know where the material safety data sheets (MSDS) are located? Do they know how to follow product directions and use any required personal protective equipment? How often do you as a manager update employee training and monitor work practices?
Now that you’re in on these dirty little secrets, what can you do? Here are some ideas:
- Talk with your product representative(s) to ensure you understand the best applications for products you use.
- Check up on your current procedures—and actual practices in the kitchen.
- Talk with your work teams about ways to battle dirt and germs safely and effectively.
By Sue Grossbauer