We noticed he was more tentative and starting to stutter around the winter holidays, but could not figure out what the pattern was. Then one early evening before dinner we gave him a slice of organic, orange American cheese (milk, salt, enzymes, annatto). He started stuttering shortly thereafter. He'd had ice cream the previous day with no issues. Then we noticed it after mac'n cheese. Upon reflection, his grandparents brought cheddar duckies to snack on during the holidays. At that point we started eliminating it and did not notice a stutter. Sometimes after pre-school, when he was stuttering, I asked him how his <non-orange> crackers were and he would always say "orange" crackers. We avoided anything obviously "orange" and the problem went away in a number of weeks. It popped up again while eating chicken tenders (cheap ski lodge food) and then we started noticing that the breading in many packaged chicken tenders had annatto for color. The same with cheap vanilla ice cream. He's all good now though -- we were lucky.