TODAY’S INSTANTLY INFAMOUS “watermelon-flavored toothpaste” Obama cartoon (above) was not only published in the Boston Herald. Jerry Holbert’s shocking commentary was also sent out to his clients by his syndicate, Universal Uclick. But here’s the toothpaste-toon capper, if not the real twist:

The version of Holbert’s cartoon that was distributed to client newspapers and outlets says instead: “raspberry-flavored toothpaste” — rendering the work about as benign as floss.

So what happened, exactly? Clearly someone at the Kansas City-based syndicate had the correct judgment to call up “Rewrite!” for Holbert’s cartoon, which satirizes Secret Service failures involving incidents like that of recent White House intruder Omar Gonzalez.

That someone is Reed Jackson, associate editor at Universal Uclick.

“I’m Jerry Holbert’s editor at the syndicate,” Jackson tells The Post’s Comic Riffs. “When I saw the cartoon, the ‘watermelon’ flavor immediately stood out to me, for two reasons: First, the racial subtext that the line unintentionally introduced distracted from the cartoon’s point; and second, watermelon flavoring is only available in children’s toothpaste, so it would be a weird thing for adults to brush their teeth with.”

For both those reasons, Jackson suggested to Holbert that he replace the flavor. The veteran cartoonist’s email reply made one thing evident to the editor: No racist slur had been intended.

“Yes, he made it very clear via [email] that the racial element hadn’t occurred to him,” Jackson tells Comic Riffs.

“So I suggested to Jerry that he replace watermelon with a different flavor, and he agreed,” Jackson continues. “He’d recently seen a tube of watermelon toothpaste and thought it was an odd flavor, and it stuck with him, so he included it in the cartoon. He was happy to change it.

“I suggested something like ‘lime spearmint zest,’ but Holbert went with the simpler and more elegant ‘raspberry.’ ”

“I feel awful about the perception that it was racist, but it was nothing of the sort,” Holbert tells The Post’s Comic Riffs. “I wanted another flavor of toothpaste for the cartoon, and we had a bottle of Colgate kids’ toothpaste that was watermelon-flavored … watermelon seems to be a big flavor these days, so…I went with it.”

“It was a completely innocent attempt at humor, but it did not come across that way to some people,” Holbert continues. “I have said I am sorry for offending anyone — I never intended to do that. I never even thought about the racial element. I wish I had, but I did not. A bit dumb on my part — I should have thought it through more.”

Holbert acknowledged that after he was contacted by the syndicate and changed the cartoon’s wording, he then failed to alert his Herald editors to the change by Universal’s Jackson, who had thought it through more. In retrospect, Holbert tells Comic Riffs, that failure to do so was a “big mistake on my part.”(Holbert’s Herald editors have said they didn’t have an issue with the cartoon as submitted.)

Holbert says his aim was only to skewer the lax security surrounding President Obama. “Now it has all blown up around racism,” the cartoonist tells The Post’s Comic Riffs, “which is something I detest. I never make racist humor.”

Update: In an apology published Thursday in the Herald, Holbert wrote in part: “Unfortunately, my choice of toothpaste flavors evoked old stereotypes, which I mistakenly overlooked. I will do my absolute best to be more careful and sensitive to all angles suggested by elements in my cartoons in the future.”

Amid the outcry, Holbert — who has been honored by the National Cartoonists Society and the New England Press Association — and his newspaper have publicly apologized for the cartoon. Yet the incident serves as a resonant reminder of at least two things:

Unfortunately for Holbert, he can’t put the toothpaste of controversy back in the tube.

And a good editor is always the best protection against a stained reputation.