This is a common food labelling hack in the US when a manufacturer has a product like sausage or bacon which would normally be treated with sodium nitrate (curi

This is a common food labelling hack in the US when a manufacturer has a product like sausage or bacon which would normally be treated with sodium nitrate (curing salt) to maintain color and taste. When 'nitrate-free' became something the organic food crowd wanted to see on the label but grey meat was not going to be appealing in the package you suddenly found a lot of recipes that included some sort of celery extract because it was high in available nitrates. tl;dr in the US this was more about nitrates and color of packaged meat than it was about glatamates.