MSG sensitive people such as migraine sufferers are all too aware that gravy is dangerous territory because it nearly always contains E621, otherwise known as monosodium glutamate. Gravy and stock manufacturers know you know this and so have to conjure up new and inventive ways to force feed it to you without your knowledge.
Bisto may well be the "nation's favourite gravy" and I'm sure their dedication to "making your meal a success" is second to none, but this doesn't preclude it from being full of crap. Nevertheless, at least they admit to this on the packet. Other companies aren't so up front. They'll cheerily trumpet that their gravy is "free from artificial flavours and additives" despite containing MSG in one guise or another, and they can get away with it scot-free because, technically it's true. MSG is merely a crystalline salt - a chemical extraction if you like - of glutamic acid; a naturally occurring amino acid found in many untampered-with foods including certain cheeses, peas, tomatoes and corn. Natural or not, overdosing on the stuff isn't going to be a pleasant experience if it's one of your migraine triggers.
So how do you inform people that your product contains MSG without setting off any alarm bells? Call it something else, that's how. In effect you'll see super-wholesome ingredient lists "free of artificial additives" which feature 'natural flavouring', 'yeast extract' or 'hydrolysed/autolysed protein'. Yeast extract is free glutamic acid released from yeast cells through fermentation, while hydrolysed or autolysed protein is created by chemically breaking down cereals or legumes into their constituent amino acids, including free glutamic acid.
Strangely enough all these homely, warm and fuzzy techniques serve to artificially enhance the flavour of bland food by bombarding the brain's receptors with excitotoxins capable of damaging or destroying its neurones. Nothing like MSG then. Bottoms up!