I have what should be a silly question, but apparently isn't.
I've recently started working for a new company (fresh cut produce). None of our thermometers are certified, as we have no critical temperature checks. We record wash water temperatures for which we have set parameters, but from what I understand that's a quality/shelf-life check. We still do daily thermometer checks with an ice bath to ensure our measurements are accurate (our dial thermometers can be manually adjusted if found out of spec).
I was alarmed to discover that QA keeps and uses a large glass thermometer to verify the temperature of the ice bath. Although it is kept well away from production, it seemed to me an unnecessary item (risk) to have. The response I got from the QA manager is that an auditor challenged us on the properly prepared ice bath having a "known" temperature.
Does anyone know where I might find scientific evidence to validate the temperature of an ice bath for thermometer checks?