1st solids

My baby has decreased her formula intake for the past 4 days I called our pediatricians office today & was advice on starting 1st foods & also go up on the nipple size. My LO is 5 months 1 wk. She currently is on nipple size 3 & no purées/solids. Per their advice I just gave her pear purée but she only had very little intake almost nothing. My question is what do I do with the rest? It comes in a plastic container I couldn’t find the jar ones 1st solids only 2nd solids in jar at my local store😞 so I got her the plastic ones because of that. Can anyone tell me how to properly storage them? & how long would it be good for? Please no judging I’m a first time mom & just want to make sure I do it right for my baby.

Edit: Thank you ladies it seems like she was coming down with something maybe that’s why she had a decrease on her formula intake, she developed symptoms yesterday night/early morning she was diagnosed with a viral infection today at the ER. So maybe it was a way to say she wasn’t feeling to well or something was coming up. Again she didn’t had any symptoms until last night/early today.🤷🏻‍♀️ They didn’t relate it to that but me as a mom did lol😂