MSG and In his tea do rhyme and and have the same amount of syllables. There is even an S in the middle of the phrase which makes them sound Phonetically more similar. I can see how you would hear MSG instead of in his tea. Your worldly mind must have been watching the news in the past year and made aware of the soup controversy involving MSG as a poisonous ingredient. No one wants to buy soup with this stuff in it. This compounds the reason why your subconscious would make this association, since it is of-the-world.

Santa's_Little_Helper, this process of our minds filling in the blanks has been best explored in Psychoanalytic and Gestalt Psychology. Do look into them.

Hope to have been some help with your questions, and maybe given some direction to your quest. Search diligently for the truth under every rock and behind every corner. There is no telling where it will turn up.