When Richworth first brought out frozen boilies the trick was to let them go a bit mouldy in the bags and then use them.I was fishing fruit flavoured fishmeal boilies one year.
One particular day, it was hot & humid, & they started to sweat, in no time at all they were covered in a mould, and the bait got better and better, the following day they stank and we were still catching loads. So after that moment, I never throw them away, and if mould appears on them I'm still not phased Wayne.
allegedly it was the sugars in the bait coming out onto the surface…..
Regarding freezing or re-freezing baits; I like to either buy frozen bait that I can collect direct from the maker, or freshly rolled bait that I can freeze myself. I don’t trust deliveries of frozen bait (after one or two bad experiences of stuff getting delayed in transit).
when I actually fish I tend to use very little bait and fish very short sessions - so any left over tends to be minimal amounts which does get refrozen.