The process
for sanitary stainless steel equipment fabrication starts with the selection of the metal
and special handling of the material to prevent contamination. For many food and chemical
producers, the level of finishing on processing equipment is determined by federal, state,
and local regulatory agencies. In sanitary applications, the finish, as well as the
material, must be designed to mitigate risk and allow for effective and efficient cleaning
and sanitation.
A bead blast
finish is commonly used for exterior equipment surfaces and can be found on the interior
food contact surfaces. The bead blasting process utilizes bead material such as glass or
ceramic beads to produce a non-directional, textured surface with a soft satin appearance
and low reflectivity. The finer the blasting media, the more corrosion-resistant the surface
performance. The RA values are typically higher than 45 but are dependent on the blasting
process and the stainless material.
Bead blasting
is commonly used when a uniform finish is desired in structural, material handling, or food
handling applications. Many food manufacturers utilize a bead blast finish on the food
contact surface area; all who have the equipment and sanitation protocols that comply with
their industry food safety regulations.
Electropolishing is an electrochemical process
that removes surface material from stainless steel. It produces an extremely smooth,
mirror-like finish. The process includes immersing the stainless-steel component into a
temperature-controlled bath of electrolytes charged with a DC power supply. Electrolytes
used in electropolishing are concentrated sulfuric and phosphoric acid
solutions.
Electropolished food contact surfaces comply with sanitation
protocols, provide operational sanitation performance beyond compliance, and significantly
reduce food attachment, which drives food safety goals and sanitation efficiencies for food
processors.
Under 200X
magnification, the 304 Stainless electropolish finish shows six times the smoothness
measurement than the 304 Stainless Bead Blast
Finish.
As
microorganisms attach to surfaces, they become more resistant to both physical and chemical
sanitation practices. It was determined that out of eleven different finishes tested, the
electropolished finish was the most resistant surface to bacterial attachment.
Electropolished food contact surfaces commonly
optioned in Mepaco’s cookers, mixers, pump feeders, vacuum stuffers, screw conveyors and
inside chutes of dumping equipment. Agitators, shafts and augers can also be
electropolished, to treat the entire food contact surface. Electropolishing services are
offered in-house by experienced technicians; there is no dependency on outsourcing.
Mepaco’s food
processing customers have more discretion in choosing equipment finishes, even in food
contact environments. The type of food product, bacterial count, manufacturing function, and
sanitation procedures all have an impact on the requirements of equipment
finishes.
