You could connect to an on-premise server. As a bonus, the manufacturer cannot disable them and extort money in this case.
If the only usecase is monitoring, then why make the fridges anything else but report-only?
No firmware updates. no admin configuration. no ssh backdoors. just a transmit-only system
They most likely are. Third party techs then access them over Citrix or VPN/RDP. There could be some cloud portion that aggregates data or pushes policies and schedules as well.