Leaving a solid block of cheddar cheese vacuum packed but not refrigerated overnight is not recommended and could pose potential food safety risks. Cheddar cheese, like most dairy products, is perishable and needs proper storage to prevent bacterial growth and spoilage.
Vacuum packing can help slow down the process of spoilage by reducing exposure to air, but it is not a substitute for refrigeration. Without refrigeration, harmful bacteria can multiply rapidly at room temperature, especially during warmer weather.
The general rule for perishable foods, including cheese, is the "2-hour rule." Perishable items should not be left at room temperature for more than two hours. This is because bacteria can multiply rapidly in the "danger zone," which is between 40°F (4°C) and 140°F (60°C).
If a solid block of cheddar cheese is left at room temperature overnight without refrigeration, it's best to discard it to avoid the risk of foodborne illness. While vacuum packing can provide some temporary protection, it is not a guarantee of safety when it comes to perishable foods.
To ensure the safety and quality of cheddar cheese, store it in the refrigerator at or below 40°F (4°C) and keep it properly wrapped or sealed to prevent exposure to air and potential contamination from other foods. If you need to transport cheese or keep it at room temperature for a short period, make sure it remains within the 2-hour window and refrigerate it promptly afterward.