The ผงชูรส question

ผงชูรส, literally 'powder that lifts the taste', is monosodium glutamate (MSG). Many street cooks add a spoonful to stir-fries and noodle broth, and the jar often sits next to the sugar and fish sauce. Food-safety regulators such as the US FDA treat it as generally safe and most people notice nothing, but some prefer to skip it. Saying ไม่ใส่ผงชูรส 'no MSG' is an ordinary request that cooks hear every day; nobody takes it personally. Two honest caveats: a broth made in the morning may already contain it, and some seasoning sauces contain glutamate too. A stall sign reading ไม่ใส่ผงชูรส is a selling point, not a warning.