One person upset at Mayor Bloomberg for pushing for salt reductions in packaged foods let him know it directly in a “nasty” e-mail.

The mayor seemed none too pleased.

“Somebody just sent me a really nasty e-mail in the middle of the night. It’s unbelievable,” the mayor said on his weekly WOR radio show.

“You shouldn’t demand it. This woman went on and on (that) we should tell people. That’s all we’re doing, we’re telling ’em.”

Minutes later, when discussing his drive to boost volunteerism, the e-mail issue was still nagging at Bloomberg.

“Let’s be the leader, which New York should be in all these things. There’s an enormous number of volunteers. You don’t have to do it. I don’t need a nasty e-mail about it. You don’t want to do it, don’t volunteer,’ he said.

How the irate sodium defender got the mayor’s e-mail address wasn’t addressed.