For instance + "colon".
Take Bartlett pears, for instance: unless they are treated with exactly the right amount of 1-MCP at exactly the right time, they will remain hard and green until they rot, and consumers who experience this will be unlikely to purchase them again.
I remember being told that we typically don't use a colon after for example or for instance, instead we use a comma. I am more familiar with "Take Bartlett pears, for instance, unless they are... Why is using a colon correct?