Yes, this is a grammatically correct sentence. But I feel I must double check that you really want to say 'dairy'? If so, an example where this might be appropriate is: you are a health inspector putting pressure on a milk producer to improve their cleanliness, but you are also good friends in real life and therefore you don't want your professional pressure to interfere with your personal friendship. So you make this apology in an attempt to keep a good personal relationship between you. However, it's possible that you mean 'diary' (a written journal, if you are apologising to a student perhaps), or even 'daily' which would require some changes to the grammatical structure of the sentence.