Paula-
My own suspicions are of grains, baked goods in particular. But it could extend to meat and dairy due to the fact that this family of toxins can pass from grain to cow to meat/milk as well. There are dozens of these "mycotoxins" and most are not broken down by heat. The defense is keeping them out of the food supply but that fails a part of the time. Also, there is the problem of bread and such that is old. Ironically, if organic with no preservatives, then the risk climbs. Penicillin would be an example of a case where the particular toxin was not harmful to humans. Something like aflatoxins on peanuts would be quite the opposite situation.

Most are neurotoxins and kind of scary. There has not been much research on the effect on humans but there has been much more on livestock. One that caught my eye causes the aptly named "staggers" affecting primarily the rear legs and wearing off as the toxin is eliminated.

Before you venture into KMT, you might just take a day and scrupulously avoid grain of all sorts. If that seems to be an improvement, then you can go deeper.

This could be anything from scattered individual sensitivities to the cause of PD - the research has not been done. My own suspicions at present are that these things are normally blocked by the BBB but that when it fails there are consequences.

I'll try to find a decent site on KMT and post it.