Not too long ago, we discussed what food processors should look for in custom-made, industrial refrigerator/freezer shelving. Food manufacturers, whether they’re multinational conglomerates or smaller suppliers of chilled ingredients/packaged food to local outlets, have numerous considerations to keep in mind when ordering shelving, such as:
- Maximum load weight
- Products being processed that might touch the shelf
- Minimum operating temperature
- Dimensions of the cold storage unit
Each of these considerations can affect what the optimal design of the shelving might include. For example, some food manufacturers might need to apply a special coating to their refrigerator shelving to inhibit the spread of bacteria or use a certain finish to make the shelving easier to clean.
Which coatings and finishes are the best for custom refrigerator/freezer shelving? There are a few good coatings and finishes that could be used, depending on the application.
There are many different types of antimicrobial coatings, each with unique characteristics. The antimicrobial coatings used by Marlin Steel are “active” coatings that use silver ions to attack microbes such as:
- Bacillus Cereus
- Mycobacterium Tuberculosis
- Escherichia Coli
- Salmonella Typhimurium
- Streptococcus Mutans
Just to name a few. The coating is applied in the same way as any other thermoset, electrostatic-grade powder coating, with varieties including TGIC-Polyester, Urethane-Polyester, Hybrid, and Epoxy.
The silver ions in the powder coat are moisture-activated, migrating to the surface of the coating where they can attack microbes.
Using Antimicrobial coatings helps to limit the spread of bacteria on your shelving to a certain degree. However, because the coating relies on an active ingredient, it will eventually require a new coating given enough time.
Teflon® Coatings from Chemours
Chemours’ Teflon® family of coatings are incredibly popular for use in the food industry. Their non-stick characteristics make them ideal for use in refrigeration units where the products being stored might otherwise adhere to the surface of a shelf.
It’s important to note that there are actually four different formulations of Teflon®:
- Polytetrafluoroethylene (PTFE)
- Fluorinated Ethylene Propylene Copolymer (FEP)
- Perfluoroalkoxy (PFA)
- Ethylene Tetrafluoroethylene (ETFE, or Tefzel®)
Each of these coatings has its own unique characteristics for temperature tolerances, but most should hold up fine to standard refrigerator temperatures. The Tefzel® coating is especially effective at protecting shelves from contact with liquids, as it is the least porous of all the Teflon® coatings.
Rather than applying a coating of extra material to food shelves, some food makers prefer to have the metal used in their shelving be finished in different ways. One of the most reliable and popular finishing processes that food makers use for shelving is electropolishing.
The process of electropolishing a metal shelf strips away microscopic imperfections that food or bacteria might cling to, leaving a smooth, shiny, and very easy to clean surface.
Another benefit of electropolishing is that it eliminates many microscopic surface fissures (i.e. cracks) in metal wires or sheet metal that could cause the metal to shatter under the force of a sudden impact—such as a 100+ lb. side of beef being dropped onto a shelf.
In stainless steel alloys, electropolishing can enhance the chemical resistance of the metal as well. This helps stainless steel shelving last longer in commercial refrigerators/freezers.
For most refrigerator shelving applications, electropolishing grade 304 or 316 stainless steel and leaving it uncoated is ideal. It allows for one of the best balances between form, function, and cost of any of the coating/finish options that food makers can have.
For some applications, it can be perfectly fine to use just the plain, untreated, uncoated steel for refrigeration—IF the steel has the right chemical corrosion resistances. Plain steel rarely fits this category. Instead, grade 316 SS is a better choice because of its innate resistance to chlorides and moisture.
It is important to note that using electropolishing does provide a superior overall piece of refrigerator shelving compared to a plain finish—it’s easier to clean, more resistant to chemical corrosion, and even helps make the frame of the shelf more resistant to shattering by eliminating microfissures.
Need help creating the perfect piece of refrigerator shelving for your short or long-term industrial food production applications? Contact Marlin Steel today!