Beverage and packaged foods are often made up of several materials that react to studio lighting differently, which results in multiple undesirable reflections.  Take for instance, an everyday item such as a humble bottle of sauce.  This is often contained within a clear bottle made from either glass or plastic (with curved and straight surfaces) filled with a viscous liquid (causing the light to bounce back at many different angles) incorporating a glossy printed label (sometimes with metallic writing) and most likely topped off with a shiny cap.  With packshot photography compounding these issues is any additional outer packaging that the product container may come in and props used in the photo shoot. 

Difficult for any photographer with little or no experience in such matters.  If a vendor wants to invest in excellence Tim Salix has perfected techniques, acquired equipment and sourced specfic materials to overcome such hurdles.