Where the
world gathers for metal finishing
Q&As since 1989


-----

Food safety of phosphate coatings

I am from the biscuit manufacturing industry and we currently use a stainless steel wire on our wire cut machine that cuts the individual pieces of dough for the biscuits. In an effort to reduce downtime from wire breaks, we are considering using a carbon music wire which may have better fatigue resistance. The wire is a Roslau product listed as having a phosphate coating. I would like to know what type of phosphate coating it is likely to be, and whether it is safe for food contact. Also if there are any other processing byproducts we should be aware of and how to clean them satisfactorily.

thanks,

Tom Prisk
Food manufacturer - Brisbane, Queensland, Australia
2007

---

I can't believe that a phosphate coating would be a good idea, Tom. It's not an abrasion resistant finish, and it's not very corrosion resistant, in addition to raising sanitary issues.

I would try getting some stainless steel wire electropolished -- which would make it smoother and less clingy and freer of stress risers -- and see how it lasted, because electropolished stainless steel is the ideal food handling material. If the work hardening of stainless steel still kept the life short I would look into electroless nickel plating or chrome plating of the steel wire.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

---

I would prefer to use a stainless with a higher strength or to increase the diameter a few thousandths. I do not like the music wire idea as it is too hard and phosphate coating will end up in the cookies and making cleaning difficult.
What SS do you currently use?

James Watts
- Navarre, Florida
2007