Which method of reducing the oxygen environment of food does not require regulatory variance approval?

Producing foil-wrapped baked potatoes is the method of reducing the oxygen environment that does not require regulatory variance approval. This is primarily because this technique is considered to be low-risk when it comes to food safety.

When potatoes are wrapped in foil, the foil creates a barrier that limits the exposure to oxygen, which can help inhibit the growth of aerobic spoilage organisms. However, it's important to ensure that these potatoes are cooked thoroughly and maintained at a safe temperature, as improper handling can still pose food safety risks.

The other methods listed often involve more complex processes that could lead to food safety hazards if not managed properly. For example, cook-chill and sous vide processes involve specific temperature controls and time commitments to ensure safety, and therefore, they require regulatory approvals to ensure that they are being conducted safely under controlled conditions. Similarly, vacuum packaging can promote the growth of anaerobic pathogens if not performed correctly, which is why it often seeks regulatory approval. These methods require detailed monitoring and adherence to food safety standards due to the potential risks involved, making them subject to regulatory variance.