For QuickBooks Online (QBO) Plus, you can enable the Track stock feature. Once that's done, you can proceed with adding stock products in QBO.
Here's how:
Highlight the Sales tab.
Select Products and Services.
Tap the New button.
Choose Stock.
Enter the name of this stock item as you'd like.
To continue this process, take a look at this article: Add stock products in QuickBooks Online. It also appears that you've created a post with the same topic. My colleague @MaryLandT answered it for you. Check out this link for more details.
Be advised, it's a little bit different managing food stocks due to spoilage. I suggest consulting your accountant for more info on how to proceed with that.