Possible Clues:

• Holy food from Switzerland?
• Hard Swiss cheese
• Rennet's first to be accepted by man before making cheese
• Man eating piece of Roquefort before Swiss cheese
• Cheese for French onion soup
• Holy food from Switzerland
• Firm pale cheese with holes
• Cheese
• One might eat this and perhaps get grey and rue how holy it sounds
• Sounds as if this got grown here to be full of holes