Q:

Is there another word for a sub-team specialized in a certain subject matter please?

Is there another word I can use to name a sub-team specialized in a certain subject matter? A few of us within a leadership group are getting together across job functions to form a sub-team for Food Safety. Purpose of group is to update each other across related functions, agree then communicate to the clients to whom we consult. Thanks in advance!

A:

Although there's nothing wrong with either unit or committee per se, if sub-team has already been ruled out, than so must the larger team be ruled out—and team is synonymous with both unit and committee.
I had been going to suggest task force, which is a group formed for a specific purpose, but a comment under the question clarified that the sub-team would be permanent—and task forces are normally disbanded when their jobs are done. (Although not commonly done, so it would be a little unusual, the term could be used on a more permanent basis if it was desired.)
However, drawing from terminology used in technical and professional fields, I suggest the following:
subject-matter expert (SME)
From Wikipedia:

A subject-matter expert (SME) is a person who is an authority in a particular area or topic …
In engineering and technical fields, an SME is the one who is an authority in the design concept, calculations and performance of a system or process.
In the scientific and academic fields subject matter experts are recruited to perform peer reviews, and are used as oversight personnel to review reports in the accounting and financial fields.
A lawyer in an administrative agency may be designated an SME if he or she specializes in a particular field of law, such as tort, intellectual property rights, etc. A law firm may seek out and use an SME as an expert witness.

Of note is that the person who wrote this article is pronouncing SME as if it were an initialism: "an s-m-e." However, in my professional line of work in the technology industry, everybody I know has always pronounced it as an acronym: "a smee."
While SME can refer to an individual who is an expert in a field, it can also refer to a group of such people. So when, for example, somebody means to say, "Ask the group of experts on the design team," they can either say ask the design SMEs [people] or ask the design SME [group of experts].
At least in my experience, SME is often kept singular, whether we refer to an individual or a team. We can also say that somebody is part of a SME. It's a blurring of the definition that's understood from context.

So, in the case of this question, you could say the same thing in a few ways, where its reference to a person or group is implied.
As a group:

Let's create a Food Safety SME.

As inviduals:

Let's create a team of Food Safety SMEs.

Ambiguously (where it could refer to either a group or an individual):

Let's use a Food Safety SME.

