From: "Cindy Mejia" <[log in to unmask]>
> Sorry I don't remember the brand, it had KOSHER written out not the usual
> symbols on the package. I know it was the hot dogs because I reviewed
> everything else she ate that day and that was the only new item.

First, Kashrut is supervised.  A complaint will be taken seriously.

Second, sodium lactate is not supposed to be diary.  References:
http://ourworld.compuserve.com/homepages/stevecarper/experts.htm
http://www.foodallergy.org/allergens.html

Third, you daughter may be allergic (or intolerant) to other, non-diary, ingredients in the hotdog.

Fourth, maybe they just weren't fresh...

I am not trying to be anal.
We had the same thing with our daughter - out of the blue, she'd react to food that was not supposed to have any diary in it.
Finally we found out that she is also allergic to raw eggs.  Mayonnaise was the culprit...

Unfortunately, the process of elimination is more alchemy than science.