Learn Italian: Ogni bagaglio va ispezionato attentamente. - Every bag must be inspected carefully.

Both phrases mean exactly the same thing: 'must be inspected'. Using the verb andare (in this case, va) plus a past participle is a special construction called the passive of necessity. It is a very common and natural way in Italian to express that an action must or needs to happen, especially for rules, instructions, or strong recommendations.

If we changed the subject to the plural 'all the bags' (tutti i bagagli), how would the verb change?

Both the verb andare and the past participle have to agree with the subject. Since bagagli is masculine plural, va becomes vanno, and ispezionato becomes ispezionati. The plural sentence is: Tutti i bagagli vanno ispezionati attentamente.

Why is it ogni bagaglio (singular) when the rule applies to all luggage in general?

The word ogni means 'every' or 'each'. In Italian, it is invariable (it never changes its ending to agree with gender or number) and must always be followed by a singular noun. This works exactly like English, where we say 'every bag' instead of 'every bags'.

Can I use this andare passive in the past tense to say 'Every bag had to be inspected'?