Is non-polished stainless steel considered a sanitary surface?
Our company just had a piece of equipment manufactured. It has arrived and to my complete and utter dismay, the exterior and interior are composed of non-polished stainless steel. It looks as though it is almost an anodized stainless. Does anyone have any experience with this type of finish? I can't even seem to scrub the maintenance mans dirty hand prints off of the exterior, let alone running product in this large vessel which will only be a CIP cleaned surface, as it is an incredibly tall tank, with most of it that is inaccessible from the opening. This vessel is impossible to have someone have enter via a confined space permit.
Our company just had a piece of equipment manufactured. It has arrived and to my complete and utter dismay, the exterior and interior are composed of non-polished stainless steel. It looks as though it is almost an anodized stainless. Does anyone have any experience with this type of finish? I can't even seem to scrub the maintenance mans dirty hand prints off of the exterior, let alone running product in this large vessel which will only be a CIP cleaned surface, as it is an incredibly tall tank, with most of it that is inaccessible from the opening. This vessel is impossible to have someone have enter via a confined space permit.
Hi sqf girl,
It likely comes down to Product Specifications.
The 3-A Sanitary Standards (1), as well as USDA guidelines specify that all surfaces, including fabricated, welded and soldered joints, shall be at least as smooth as a No. 4 (150 grit) finish and shall be free of pits, folds, crevices, cracks, and misalignments in the final fabricated form.
characteristics of food contact surfaces - Stainless Steel.pdf 972.02KB 25 downloads
In the majority of applications, a finish at the high end of No. 4 is considered food grade (see Stainless Steel Finishes sidebar). This finish is achieved using a high-grit abrasive in the range of 150-220 and is identified by short, parallel lines that run the length of the material. The success of the finish can ultimately be determined by a surface roughness average (Ra), measured by height in millionths of an inch (µin.), or microinches. A profilometer determines Ra values by moving a diamond stylus across the workpiece’s surface for a specified distance and using a specified contact force. It measures small surface variations and calculates their average to determine the roughness. In most food-grade applications, 60-36 Ra is achieved with 150-220 grit. Because milk products spoil more quickly and carry more bacteria than other food and beverage items, dairy applications should have a finer finish, No. 4A, which is 40-24 Ra and achieved with a 220-grit abrasive or finer.
What Charles said. Request information on meeting the 3A standard guidelines.
Additionally, any new stainless surface should be passivated before using to help ensure it does not pit or corrode...in case you didn't know.