I've developed this quick trick after reading a lot of food labels.
If the nutrition label says it contains any cholesterol, it's definitely not vegan.
This is based on the idea that cholesterol is only produced by animals, never by plants. Therefore, a vegan diet is completely free of dietary cholesterol. The presence of cholesterol in food must indicate that it is of animal origin of some kind.
This shortcut has served me pretty well. When I suspect that a packaged food is non-vegan, a quick glance at the nutrition label will confirm that to be true. However, I'm not sure about the veracity of this corollary statement.
If the nutrition label says
0 mg cholesterol, it's vegan. (Is this true?)
Are there any examples of packaged foods that say
0 mg cholesterol but aren't vegan? In this case I'm setting a low bar for what it means to be vegan: just contains no meat, eggs, or dairy. Could a packaged food contain meat, eggs, or dairy products but still say 0 mg cholesterol? How could that happen? Assume the label accurately reflects the cholesterol content.