Materials Used in Food Processing Equipment

Designing for Safety

Ask any food manufacturer what their top concern is and almost all would reply with “food safety.” It is routinely listed as a primary focus across the board, and 2022’s outlook is no exception. As consumers, we rarely think about all that goes in to producing, packaging, and transporting food to our local supermarkets. But for food manufacturers, the journey from farm to plate often begins with equipment design.

The components that make up this equipment then must be strong, durable, and of course safe to use with food products. Here are some of the major materials we use when building industry-leading food processing equipment.

Stainless Steel

Steel becomes “stainless” when chromium is added to the alloy mix [1]. The chromium forms a passive film that essentially protects the material from corrosion and staining – hence its namesake. Stainless steel also has several other beneficial properties:

• In addition to corrosion resistance, it is also heat-resistant and can withstand high temperatures without deforming.
• It has superior “biological cleanability” when compared to aluminum and is on par with glass. This fact makes it an ideal material for food processing environments. [2]
• Stainless steel is relatively easy to form and weld, making it an ideal material for fabrication.

While many alloy variations are available, food processors typically require the 304 or 316 variations. Which one to use depends on the application. 304 is suitable for most uses, while 316 would be required for extremely harsh or corrosive environments (such as briny or salty foods).

Maintaining a smooth surface free from pits and crevasses is essential for minimizing dirt build-up and potentially hazardous bacteria. All of Innotech’s equipment is designed for a wash-down environment to minimize risk from contaminants.  

Fun Fact: Did you know that the 304 variant was patented after it was developed for the building of a wedding gift?!

The Krupp family was the premier German weapons manufacturer from the time of the Black Plague and 30 Years’ War (over 400 years ago!) until the end of WW2. Following a controversial ordeal and death of her father, Bertha Krupp inherited the company as a teenager. Kaiser Wilhelm II, leader of Germany at the time, arranged a marriage for her due to his feeling that it would be unacceptable for a woman to run the company [3]. She gifted her groom the Germania, a 154-foot two-masted racing yacht, which was built in the Krupp shipyard in Kiel [4]. They used a nickel-chromium steel alloy for its construction, which would be patented by the company a few years later. That variant is what we now classify as 304 stainless steel.

Aluminum

Not every surface of a piece of equipment will touch the product itself. In such instances aluminum may be a better material choice. The primary reason? Costs. But aluminum carries several other benefits as well:

• It is naturally resistant to corrosion without further treatment.
• The strength to weight ratio is far higher with aluminum, which is why you’ll see it used in applications such as airplanes and transportation.
• It has both high thermal and electrical conductivity. This is why we see it used for applications such as radiators.

Aluminum however can react with food color and flavor. Therefore, stainless steel is the better choice for any surface that will have direct contact with the product.

Plastics

In addition to metals, many food processing applications are best tackled by using plastics. The U.S. Food & Drug Administration (FDA) extensively researches and approves which materials can be used. There are two primary types:

UHMW

Also know as UHMW-PE, this ultra-high-molecular-weight polyethylene is used extensively in food manufacturing for its unique properties [5].

• This materials has a high impact straight, making it ideal for surfaces that are going to see a lot of wear and tear.
• It is considered a self-lubricating polymer and requires no additional lubrication.
• It can operate in high-temperature ranges (up to 180 deg F).
• It is unaffected by water, organic alcohols, ketones, and non-oxidizing acids.

Due to the strength, durability and impact resistance, UHMW is found in many conveyor systems, inspection tables, chutes and hoppers. At Innotech we tend to favor use this material for the vast majority of conveyor applications (over 90%) versus acetal or HDPE.

Acetal

Acetal, acetal resin or polyaxymethylene (POM) is an engineered thermoplastic that has been approved by the FDA for use in food applications. [6] This amazingly stiff material has incredible fatigue endurance, meaning it can withstand prolonged abrasion. Here at Innotech, we typically use acetal on places with high wear-and-tear, such as guards around a chained belt. Food-grade acetal can contain metal additives so that should part it break and end up in the product, it would be detected by a metal detector before the product is packaged and/or shipped.   

Summary

So which materials do we use? The simple non-answer would be “it depends on the application!”

Having worked in a range of environments and industries for years, our engineering and design team have a commanding knowledge of the right materials to use. And how we came by this knowledge wasn’t simply through research. We have designed, built, field-tested, tweaked, re-designed and re-deployed equipment in myriad real-world settings.

R&D isn’t a department at Innotech; it’s how we operate. Get in touch with us to learn how we can innovate solutions for your processes.