According to the FDA, to be considered food-safe, a material must meet several conditions:
- It must not allow the migration of “deleterious substances or impart colors, odors, or tastes” to food
- Be “durable, corrosion-resistant, and nonabsorbent”
- Possess sufficient “weight and thickness to withstand repeated warewashing”
- Be “finished to have a smooth, easily cleanable surface”
- Have resistance to “pitting chipping crazing, scratching, scoring, distortion, and decomposition”
Food-safe metals help meet all of these conditions for utensils and equipment in the food industry. But, which metals are considered food-safe?
After all, some metal alloys may transfer dangerous particles to food, such as lead. Others may not meet the right corrosion-resistance requirements or may not be easily sanitized.
Here’s a list of the most common food-safe metals used for making custom sheet metal and wire forms in the food industry:
Cast Iron (for Cooking Use Only)
The FDA has approved cast-iron equipment for use in the food industry, but only for cooking surfaces and in utensils for serving food “if the utensils are used only as part of an uninterrupted process from cooking through service.”
For all other uses, cast iron MAY NOT BE USED as a food-contact surface. Iron without a protective material is simply too vulnerable to corrosion and oxidation.
Grade 304 Stainless Steel
Grade 304 stainless steel is the most commonly-used stainless steel alloy in use in a wide variety of industries. As a material, 304 stainless is highly useful because it can resist corrosion caused by a wide variety of chemicals and may be electropolished to a smooth, shiny, easy-to-clean surface.
However, some corrosives and excessive exposure to salt can still degrade 304 stainless steel.
Grade 316 Stainless Steel
Grade 316 stainless steel is the second-most common type of steel used today. While its mechanical properties are, for the most part, similar to 304 stainless steel, grade 316 stainless has much better resistance to chlorides such as salt.
This increased corrosion resistance is largely because of 316’s higher molybdenum content.
Aluminum is another commonly-used food-grade metal. Some key advantages of aluminum are its temperature tolerance, light weight, corrosion resistance, and low cost.
However, these advantages are offset by some weaknesses. Compared to many other metals, aluminum has a low tensile strength and impact tolerance, so it can’t take too much force without breaking.
Because it heats and cools quickly, aluminum is often used in cooking surfaces such as baking trays.
Copper has become a popular choice for cookware in restaurants, but it isn’t generally recommended for industrial food production equipment. As noted by the FDA:
Copper and copper alloys such as brass may not be used in contact with a food that has a pH below 6 such as vinegar, fruit juice, or wine or for a fitting or tubing installed between a backflow prevention device and a corbonator. –FDA Food Code 2009: Chapter 4
Basically, anything more acidic than milk poses a corrosion risk to copper equipment, so it isn’t useful for large-scale manufacturing.
As mentioned earlier, it takes more than simply having the right material to make metal food-safe. The metal used needs to have the right finish so that it can be easily cleaned/sanitized after each use.
Learn how you can get food-safe custom sheet metal and wire forms for your production process today!
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