A plant/facility’s design flaws both regarding product flow and traffic patterns strongly dictates the issues, frequencies, and degree of environmental sanitation required in your environmental sanitation program. The facility’s design blemishes or weaknesses will strongly dictate your risk assessment for each and every site in both Zones 3 and 4 in your plant. For example, a well-designed kettle deck mezzanine with accessible surfaces, frames, and overheads will both speed up sanitation efficiencies, and based upon proper design (i.e. 45 degree frame angles versus 90 degree), decrease sanitation frequencies of environmental Zones 3 and 4. By lowering the risk at each environmental site you also are able to decrease the Verification-Validation frequencies and procedures as well.
Both improper plant design in terms of structural issues inherent in high- to moderate-risk production areas and poor traffic floor design/practices can contribute to high risk for pathogens. For brevity, I’ll discuss the aforementioned. Salmonella for dry environs and Listeria for moist environs. Both can survive either in senescent vegetative or biofilm forms.
Salmonella can persist in a senescent vegetative state in relatively dry conditions occurring in a baking or a peanut butter processor. So there are numerous niches where it can survive. This dictates the Zone 3 or Zone 4 EM sanitation frequencies.
Examples include air lines, ducts, aspirators, and dry vacuums. Other areas include eroded or compromised walls, coving, insulation, overheads, conveyors, elevator buckets, fork lifts, and pallet trucks, cat walks, employees, cleaning tools, and maintenance tools. Also insects, rodents, and birds are carriers.
Listerial niches are created and selectively promoted by moisture and refrigerated temperatures. This includes drains, walls, covings, and hoses, gaskets, and O rings, along with unsealed structural tubing or railings. All these compromised areas promote biofilm formation, which a primary survival mode for environmental Listeria. Also improperly maintained sanitation items, such as squeegees, footbaths, floor scrubber components, condensation appliances, etc., all can be Listeria inoculators.
What’s in Your Toolbox?
In plants where wet cleaning of environmental areas is both permissible and feasible, typical foam cleaners can be employed to clean environmental surfaces.
Obviously when a prescribed wet sanitation is performed on environmental surfaces, the SSOP needs to include a sanitization/disinfection step with a compatible biocide. When the biocide will not be rinsed off, compatibility of the biocides’ chemistry must be determined with the surfaces being sanitized. For example, if one has galvanized steel and aluminum structures and you will be applying an acid based quaternary ammonium (QAC) or peroxyacetic acid (PAA), you either have to rinse it off or chose a neutral based QAC to avoid corrosion.
Application of wet biocides, especially for aqueous environmental, is dependent upon the target microbes. If they are sporeformers like B. cereus or fungi, a QAC or liquid PAA is not the preferred biocide to eliminate these sporeformers. Rather a foaming version of PAA sanitizer is preferred for all environmental surfaces. Foaming PAA penetrates sporecoats and provides enhanced residence time of the biocide on the target surfaces and attached microbes. As stated above, if one is applying foaming PAA to soft metals on a normal set frequency, after a 30 to 60 minute residence time, the foamed PAA should be rinsed off to avoid corrosion issues.
If you’re applying foaming PAA or foaming QAC sanitizers to drains, one can inject foamed sanitizer deep into trough, square, or circular drains including deep into the drain pipes. Also, when one applies QAC above 600 milligram/liter per U.S. EPA label instructions, QAC typically foams. That is why it’s utilized quite successfully in wet environments with proper drainage for door foaming units to control Listeria cross-contamination.