If the only thing that's worrying you is you forgot to freeze it, then how long was it out of fridge/freezer for? It's fine left out for several hours - off top of head, I think it's five. Might even be more!
If baby is feeding lots anyway, how do you feel about a bottle of formula now and then? If baby is still feeding lots then supply won't be affected. I kept some individual cartons in for these times ie when I was ill/ other child Ill and had to be with them/ work meeting etc. They still breastfed until 2 years otherwise
Squizita - it shouldn't do. Between say 6 weeks and 1 year we gave aptimal bottle maybe once a week, so nothing regular, and didn't seem to make any difference.
I also thought I would express if needed ( was back working from home from 6 weeks but had occasional meeting in office), but found it would be such a faff as I would spend all day planning on when would be a good time/ when baby wasn't feeding etc.,
for convience/ sanity sake we chose the odd bottle. Meant it was there if needed, but if not could be used another day as not opened and they last ages. If dh went out with baby he could take carton just in case also for peace of mind. 99% of time baby was fine being fed before and on return, but he said he was much more relaxed knowing it was there
We have a couple of cartons for emergencies. .. will keep them handy. Got a couple of oz this afternoon as she napped and have stashed it. Going to keep pumping and stashing it for DH to use when needed!
I was told 5 hours for expressed milk to sit out, great for night feeds for my nipple refuser if I expressed a bottle out before bed. DS has been on Aptimil and expressed breast milk since 5 days and is no windier than the average baby. I never saw a difference in him post a few breast milk feeds than post formula. It would be more about how they took the milk from the bottle (swallowing air) that might cause the wind anyway, and that's the same from expressed milk or formula. Comfort milk made him reek though, awful farts! normal formula is fine!