So, this is the TSA but: “TSA classifies items that you can spill, spread, spray, pump or pour as needing to be 3.4 ounces or smaller to fit into a 3-1-1 bag,” TSA spokesperson Lisa Farbstein said. “There has been no change in the categorization of any of these items, including peanut butter, which is a spreadable and thus falls under the 3.4-ounce limit.”

Apparently “spreadable” is one of the criteria. I’d argue anything is spreadable if you try hard enough.