Pink Colour and Pink Eye on Potatoes

Pink Colour and Pink Eye on Potatoes

Aug 1, 2019 | Jeff Honey

I was asked a question recently about pink colour on potatoes. The person who sent me the photographs was wondering if the inbound load that they were checking had pink eye. Don’t bother running for your Canadian Food Inspection Agency (CFIA) potato inspection manual, because it isn’t in there! I always tell people that it is good to be familiar with United States Department of Agriculture (USDA) manuals, as they often contain a lot more information than their Canadian counterparts. This is a good example of that.

Go to this link and scroll to the bottom of the page.  Here, you can view the USDA Shipping Point and Market Inspection Instructions for Potatoes.  Page 37 of this manual has a description for Pink Eye and a scoring guide.  It states that pink eye affects the underlying flesh of the tuber.

Also on that page, you can download the USDA’s visual aids for potatoes.  (If you have one of our potato defect posters, this is where the photos came from.)  Photos 72 and 73 on page 16 show the defect pink eye. As I began to gather more information, I found out that the potatoes in question were Yukon Golds, imported from the United States. According to the Potato Association of America, “Its shallow, pink eyes distinguish Yukon Gold from other yellow-skinned, yellow-fleshed cultivars.”

Here is a photo that I took in 2011.

While “pink eye” is classified by the USDA as a condition defect, pink pigment on the surface is a varietal characteristic. That makes it permanent, whereas a condition defect is progressive. As a varietal characteristic, it is like pink blush on a Granny Smith apple, and not a scoreable defect.

The USDA has all of their fresh fruit and vegetable inspection instructions, along with their accompanying visual aids here and here.

While the first inbound load of these Yukons was rejected, with a little communication the issue was explained and resolved.  Now you know, as well.  Never be afraid to ask questions!  We work in a very diverse industry and we are always learning something.

If you have a question about produce defects and can’t find an answer, I will try to help you out.