Out at the Fonterra factory where I’ve been working some shifts they make yoghurt. The milk is pumped into huge stainless steel vats & they add culture, heat the mix & about 6 hours later the milk & culture is basically turned into yoghurt. But between every batch of yoghurt the vats are washed down & sanitised to protect the integrity of the product. Even a small amount of bacteria will ruin the batch. When the yoghurt finally comes out of the vat & is poured into the various size containers ready to be packed & sent off to the supermarkets. The first few tubs off the line & then a few tubs in the middle of the line & then a few tubs at the end of the line are taken as samples to the lab & tested. If they detect any bacteria at all in the yoghurt thousands of dollars of yoghurt is thrown away!
But here’s the hinge pin – it all depends on the condition of the vat.