Final answer:
Without a clear definition of 'TC' and 'GF' in food safety terms and in the absence of context, it's assumed that the question refers to how long perishable food can be safely left at room temperature, which is typically no more than 2 hours according to the USDA.
Step-by-step explanation:
The terms TC and GF are not universally defined in relation to food safety. Assuming TC stands for 'Temperature Control' and GF could stand for 'Gluten-Free' neither of which directly relate to a time limit for food safety at room temperature. However, a general rule for food safety provided by the USDA is that perishable foods left out at room temperature should not be left out for more than 2 hours. This includes all types of food that require refrigeration. Beyond this point, there is a marked increase in the danger of bacterial growth and foodborne illness.
If TC refers to a specific type of food or a food component (such as Tachyzoites in the context of Biology), the safe time at room temperature can vary. Similarly, GF in another context might have a different meaning related to food safety. If this is the case, please provide additional context for more specific guidance.