Food Safety Magazine, August/September 2009

Equipment Sanitary
Design Considerations
When Purchasing

Designing a piece of equipment to be functional, efficient, economical and so it can be cleaned and sanitized quickly

and easily is a definite engineering chal-

lenge. Not too many years ago, only the first three qualities were usually

considered. The U.S. Department of Agriculture (USDA) was the only

major organization that enforced the use of equipment that could be

easily cleaned, requiring approval before such equipment could be

used in a meat-, poultry- or egg-processing facility.

Since the advent of USDA’s mandatory Hazard Analysis and Critical Control Point (HACCP) programs, sanitary design of equipment has become an absolute necessity, and more and more equipment companies are claiming their equipment is of sanitary design. However, processing companies (purchasers of this equipment) should develop their own criteria for the sanitary design of processing equipment that fits their operation.

The American Meat Institute (AMI) has developed a sanitary design checklist for the meat- and poultry-processing industry. Many of its points can be applied to other processing equipment used throughout the food industry.

Some tips to consider when deciding on a piece of new or used equipment for your plant are as follows:

1. When looking for new or used equipment, cleaning and sanitizing of the equipment should be fully considered in its design and operation.

2. The food contact surfaces on the equipment must be non-toxic, non-absorbent, non-reactive, non-corrosive and cleanable to meet FDA requirements. The regulations are specific for food contact surfaces, in or on food processing equipment. They must be non-toxic, non-absorbent of any liquid and consist of a material that will not corrode from reaction with the food product or any of the cleaning and sanitizing chemicals. Wood, of course, is not an approved food con-

tact surface since microbe-carrying moisture can soak into it and contaminate any product or utensil placed on it. The use of cadmium, antimony and other toxic metals is prohibited. In general, soft metals do not make suitable food contact surfaces. Specifically, 21 CFR, Part 110.40 states, “Food contact surfaces shall be corrosion-resistant when in contact with food.” It also states, “Food contact surfaces shall be maintained to protect food from being contaminated by any source, including unlawful direct food additives.”

3. All joined food contact surfaces must be butt-welded and free of overlap welds. Joined food-contact surfaces that are overlap-welded present a metal-to-metal contact surface and are liable to flex, crack the welds and present a hidden niche for microbial growth. These niches are virtually uncleanable.

4. The processing equipment, especially in the food contact zone, must be free of stitch or spot welds. Stitch welding leaves voids in the weld which provide potential harborage for microbes. Microbes are extremely small and many of them can fit into the voids left by stitch/spot welds. If stitch welding has to be used, the void between the welds should either be sealed with silver solder or by rewelding to fill in the voids. It then should be ground and polished. Caulk is not recommended as it has a tendency to mold, harden and fall out of the void. All welds must be continuous, smooth and polished in food contact surfaces. All welds must be free of pits, cracks and corrosion anywhere on or in the equipment.

5. All equipment and/or component surfaces should be paint-free. The strong chemicals as well as high- or even boosted-pressure water used during sanitation will, in a short time, start to strip the paint off the surface. Subsequent sanitation will rapidly cause the base metal to corrode and the loosened paint will potentially contaminate any product being processed nearby.