July 1, 2011, Victor Reusch, Ph.D., Chemist / Microbiologist

Q. What kind of products are safe for aluminum?

A. Aluminum is an amphoteric metal. That means it is subject to both acid and alkaline corrosion. If you have adequate control of your conditions (temperature, dilution) and use a product intended for aluminum, then you will have little or no problems. Birko has neutral, acid, and alkaline formulations that have been designed for and tested on popular aluminum alloys.
 Most of the dark “smut” formed during alkaline corrosion of aluminum is actually the alloy’s copper being converted to an oxide. You can relieve this type of stain safely with Birko’s Acid Brite #2.

Chlorinated products are extremely reactive with aluminum. They can only be used with great care. Although aluminum products are both light and economical, they should only be specified for use in an area where there is no concentrated (straight) chlorine bleach used. Post-rinse sanitation levels of bleach are not cause for concern.

Q. What causes yellowing and embrittlement on plastic conveyors?

A. Concentrated chlorine bleach can react with some plastics to cause damage with time. If you intend to use concentrated chlorine bleach in your belt sanitation program you must specify that fact when ordering belts and be sure that your belts are hypochlorite resistant. Some stains can be removed readily from white conveyors without chlorine bleach if the cleaning is timely and frequent. But stains that have penetrated the body of the plastic already most likely are permanent.

Q. How does galvanizing and chromating protect a metal?

A. A galvanized surface is intended to corrode in place of the metal beneath it. When the galvanizing is exhausted the metal underneath will rust. In the meantime it is best treated as aluminum in practise (no strong acids or bases) to maximize the life of the part. Modern food plants should use galvanized metals no longer. Chromate finishes present a surface that resists oxidizing conditions, but can be damaged even by dilute acids (pH 6). Neutral or mildly alkaline pH cleaners (pH 7 to 9) will maximize the life of chromated chains which are popular in the poultry industry.

We recommend Birko Liquik 2CS for foaming on chains and shackles in the poultry industry. The product will not harm the chain, yet deliver excellent results on fat and grease, with no dark smut on shackles.

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