Only claim "NEW" if it is, in fact, new (as in never been made the way you make it). You'll be called out and experience a bad PR day if consumers and media find that you're lying.

The term "new" can be troublesome and I agree with Gail.

What's the definition of new, in this case, with this product,
and in this niche?

New how? New recipe? New flavor? New and improved ...
in some never-before-seen way? Or new as in updated?

Why did you change the recipe?

So you could make it cheaper - tastier - more profitable??

Claim what you did, not that it is new. Tell the truth about what you did and there will be no comebacks.

Moriarty.

Conventional wisdom in consumer packaged goods is that "new," and in some cases "improved," are worth some extra volume provided the product is new in some meaningful way and you disclose the nature of "new."

It also used to be that you could only use "new" for a limited period of time -- like 6 months -- after which the product obviously isn't new any more.

There are probably as many exceptions to this as there are examples of where it holds. Each case should be considered on its own.

I was even involved in a side-by-side experiment (years ago) in which we compared the sales impact of "new" versus no mention of new. The "new" cell generated about +10% more volume ... but we were always concerned that there were some other variables that influenced results ... so we were reluctant to extend the findings of that particular experiment and generalize it to all instances of the word "new."

It may also depend to some extent on the product category. "New" may be more meaningful in categories without much news than in categories with a lot of news.

"New" can be helpful if you have an audience that appreciates your line and would be interested in trying something new in that line. Otherwise, its usefulness varies; there is no single research finding that will guarantee a result for your product. "New Flavor" or "New from Acme Bakery" might be more appropriate, depending on your circumstances.

Alternately, you might try, "Introducing" on the packaging as a way to tell your audience about this development without saying "new":

Introducing Buttermilk Bread
Introducing Banana-Brie-Buttermilk, our newest artisan flavor
Introducing Brie-Bacon, limited edition recipe