The truth about MSG

First of all, a message to Ajinamoto: Please call off your lawyers. I am a man of straw. And neither am I well enough known to be made an example of. To set the record straight, MSG does not make mice's head explode. Nor is it in any way toxic, at least no more than, say, salt. The US Food and Drug Administration has indeed given it the all-clear, as have the UN and European Union. It turns out that the studies carried out in the sixties purporting to show MSG had adverse side effects had involved giving mice absurd quantities of the stuff, equivalent to an adult eating half a kilo. So, while even Ajinamoto concedes some people might have an adverse reaction to MSG, it is no more than are allergic to aubergines, say, or sofas. MSG is merely a man-made glutamic acid made by fermenting carbohydrates and sugars, nothing more, nothing less.

          Now, to umami. Umami and MSG are inextricably linked, but are by no means the same thing. Umami is usually referred to as the fifth taste, after salty, sweet, bitter and sour (although some neuroscientists claim there are fifty or more tastes, but let's not get into that. It has taken long enough for the Japanese to convince the world that umami exists). When Ikeda identified it in konbu he wrote: 'An attentive taster will find out something common in the complicated taste of asparagus, tomatoes, cheese, and meat, which is quite puculiar and cannot be classed under any of the well defined four taste qualities, sweet, sour, salty and bitter.' It is not confined to Japanese foodstuffs. Cheese - parmesan in particular - and tomatoes have a powerful umami flavour, as do air-dried ham, veal stock, consomme, and Worcestershire sauce. Baby milk is rich in umami (far more than cow's milk), as is the crust on grilled or fried meat. In fact, it is often easier to describe what umami is by listing the things that are full of umami flavour, as people do tend to tie themselves up in knots on this subject - 'savoury' and 'meaty' are the words most often employed, but often the Japanese resort to translating it as 'delicious', or 'tasty'.

~Michael Booth (Sushi & Beyond: What the Japanese know about Cooking)