Many non-native English speakers are confused about the use of these two words.
Basically, they will use these two words incorrectly.
"With the yoghurt you reintroduce this bacteria."
"reintroduce" means to start to use sth again.
reintroduce ≈ reintroduce, re-introduce
Here must use "introduce" instead of "import".
You may see the word "import" on the software for the first time, such as "file→import". So you mistakenly thought that I also used "import" when putting yogurt into pasteurized milk.
What I have to say is that "import" generally refers to bringing in goods. To be precise, it refers to bringing foreign goods into our country.
Many non-native English speakers think that "introduce" has only one meaning——To introduce one person to another.
But in fact, "introduce" basically means to introduce external things into the inside. For example, people you don't know are considered external, and people you know are internal. Turning people you don't know into people you know is called “introduce”. In other words, the act of putting yogurt in pasteurized milk can be called "introduce". My example here is "reintroduce" because I want to make butter.
In conclusion, don't try to remember the single meaning of a single word. You need to recognize the word from the sentence.