My boss hade a meeting yesterday about the new rules he had a folder made up so we can read along at the end of it there was a page with my name on it it all the things he I thought I have done wrong such as not knowing how to handle food the proper way and some other things I have ben a cook for about 18 years and went to school to learn about it he also siad I have no leader ship skills or team work I was once a head chef as well every one saw this papper he wrote about me then he fires me what can I do I have thje page for proof I am also servesafe ceterfied by the state of nj

If he believes or if he has proof it is true, then it is not slander.

You look for a new job and don't expect a reference from them

... then he fires me what can i do [?]...

As Fr_Chuck wrote, look for a new job.

It's not slander. If he accused you of

not knowing how to handle food the proper way
not having leadership skills, or
not having teamwork ability,

That's his opinion, but it's not defamation. The fact that you have experience and education, and are certified, doesn't prove that your experience and training actually translate to proper performance.

I will add that this was very poor employee relations on the part of your boos. To hold an employee up to ridicule like that. But its not illegal or actionable.

Unless he made specific statements of fact, like JC did so and so to this dish and that was improper prep and his statements were not true, then you might have a case.

But since most employment is at will meaning you can be fired for any reason, it really doesn't matter what he said. The leadership and teamwork issues are pure opinion so not actionable. The only thing that might be actionable is the food prep and you would have to go to court and challenge him to prove the statement. And I'll bet he is prepared to do so.

... The only thing that might be actionable is the food prep ...

And that is certainly not defamation per se. Therefore you would have to prove damages, something that would be nearly impossilbe to do.