When talking about defrost, we usually talk about temperatures below 10-12ºC that are used in some workrooms, but we normally talk about refrigeration rooms, so we think about preservation or products freezing.
In the preservation of frozen products, we can talk about diverse temperatures, but in the main cases we will get close to 0-2ºC to get a better preservation so we can sell our products without losing its value. But to achieve those temperatures in the workroom a chilling focus that will be in negative temperatures will be needed.