How to clean food stains on a carpet?

Tea, coffee, pizza, pasta, soup, those are all examples of organic (food) stains. An organic term in this example is used as opposed to synthetic (colored dyes).
The best cleaning agent that you can use for organic stains would be oxidizers. OxiClean brand is a very good example of an oxidizer cleaner.
In the carpet cleaning industry, we use concentrated oxidizer powder. The brand that we use at A&K Carpet Cleaning is called Boost All from Interlink Supply.