Jason Kelce Anti-Foot Washing Stance Dangerous, Says Natural Soap Maker

Jason Kelce's recent -- maybe serious, maybe not -- revelation he doesn't wash his feet left one soap maker grossed out ... but she does say he's on the right track in one regard.

Here's the smelly deal ... the ex-NFL'er claimed on social that he never washes his feet and people shouldn't trust the "diabolical liars" at "big soap." Now, maybe he was for real... or maybe he was joshing, but in any case ... his remarks caught a lot of people's attention.

Count Cynthia Jennings among those folks ... she's the owner of Sweet Harvest Farms -- a manufacturer of organic, natural soap -- and tells TMZ she sure as hell hopes JK is just messin' ... 'cause not washing your feet is not just plain nasty – but dangerous. She explains why in our interview, but says JK can be helped.

Interestingly, CJ says Jason is totally right when he says he is against "big soap" -- meaning, all the giant soap conglomerates we all know from the drug store/supermarket, etc. -- ‘cause, in her view, that stuff isn’t even real soap ... so she says Jason's right to be wary.

Cynthia says most big-name soaps are actually designated as a “beauty bar," which she notes include ingredients such as petroleum, esters, alcohols, lower grade oils, waxes and detergents -- in other words, not great for the bod ... at least that's her opinion.

She dropped some further knowledge, saying the FDA years back started to levy hefty fines for companies advertising their products as soap when they were, in fact, just beauty bars.

In other words, legit soap is tough to make ... and CJ is only 1 of 40 true soap makers in the country.