Can the new owner ask me to take a criminal record check I never had to do before?

In most cases, yes — a new owner generally can ask existing staff to complete a criminal record check as part of settling into how it runs the business, even if the seller never required one. Continuity of employment under the Employment Standards Act, 2000 protects things like your accumulated service and related entitlements; it doesn't freeze every workplace policy exactly as the old employer ran it.

A new owner is generally allowed to introduce new screening requirements, provided it applies them in a way that doesn't single out or discriminate against particular employees for reasons unrelated to the job, and provided the request is reasonably connected to the role — this comes up often where a role involves handling money, vulnerable people, or sensitive information.

That said, how a record check is handled matters: you should be told clearly why it's needed, what will actually be checked, and how the results will be used, and a minor or unrelated finding shouldn't automatically be treated as grounds to end your employment. If you're uncomfortable with the request, ask what specifically the new owner is checking for and why, before assuming the worst about what refusing might mean.