Click the ingredients tab in your link and you will see sugar listed. You aren't seeing it on the nutrition label because the FDA allows you to pretend there is

Click the ingredients tab in your link and you will see sugar listed. You aren't seeing it on the nutrition label because the FDA allows you to pretend there is no sugar as long as you have less than 1g of sugar per serving. So, make the serving size small enough, and almost anything can show no sugar on the nutrition label. I believe you can also use the term "sugar free" as long as you have 0.5g or less sugar per serving.