One of the most widely used condiments is tomato ketchup. As a home canner I make and can home made tomato ketchup. However, most people buy ketchup with the most popular brand being Heinz. Heinz has been making ketchup since 1876! Years ago I worked one summer in the lab of a tomato processing facility. Well actually they also processed beets, asparagus and cucumbers as they came into season but the bulk of their work force was needed for the local tomato harvest. Tomatoes arrive at the processing facility from local farmers in huge tomato wagons. [Relatives grow tomatoes commercially for the processing plants which is where I get my hampers of tomatoes from each year.]
Tomato ketchup starts with a base of tomato paste that is made at the tomato processing facility. From there the tomato paste is passed on to the tomato ketchup lines in another area of the same facility. Tomato ketchup consists of tomato paste, white vinegar, sugar, salt and seasonings. If you look at the ingredients on a Heinz ketchup bottle, liquid sugar is listed. This is now high fructose corn syrup which explains why it is harder for a home canner to duplicate the flavour and texture of Heinz ketchup.
Here is a video I found showing how Heinz tomato ketchup is made and bottled from the tomato paste stage. The tomato paste has undergone laboratory testing prior to going to the ketchup lines. Quality control is important for ketchup not only from a safety aspect but also to be sure the ketchup meets taste and thickness requirements. Heinz ketchup is made to a thickness so that the velocity measures at 10 cm of flow in 10 seconds. This is known as the 10 cm rule. The blue bag in the video is their secret blend of seasonings.