In food industry, hygiene is a primary concern, as manufacturers need to comply with both legislation and consumer expectations – high quality product. The hygienic state of a surface is thus a critical parameter with respect to the performances of the production process and to the final quality of the product.
Biofilms is defined as “a collective of one or more types of microorganisms that can grow on many different surfaces. Microorganisms that form biofilms include bacteria, fungi and protists” – Live Science (2016)
Processing plants like pharmaceutical, brewery, beverage and dairy sectors need to adhere to strict hygienic standards and guidelines. The legislation limits beer spoilage organisms, e.g. bacteria, brewing yeast and wild yeast cells, in the final product such that hygienic fabrication and operation are required to guarantee food safety to meet final product specifications.
In brewing process plants, brewing equipment like fermenters, tanks, distillation columns and heat exchangers is factory‐built. However, many of the small‐bore pipes and their interconnections are bought from manufacturers and joined on‐site. These pipes are inaccessible from the inside so site welding is more difficult to control. Inadequately welded joints can compromise product quality in an otherwise hygienically designed plant. Poorly welded joints encourage biofilm formation and this may lead to microbial‐induced corrosion.
Poor alignment and welding lead to dead areas on joined pipes that encourage biofilm formation
Good orbital welding requires matched pipes which are correctly aligned and a minimum overlap of 95%, preferably in the range 90–100 ± 10%.