In cheese making, cheese blocks are waxed by dipping into molten cheese wax / liquid paraffin maintained at $104\text{--}121^\circ\text{C}$ ($220\text{--}250^\circ\text{F}$) for 5 to 6 seconds. This high temperature instantly sterilizes the surface mold spores, flashes off any surface moisture, and deposits a thin, flexible, airtight protective barrier.

Biochemical stages and kinetics of cheese ripening:

• Lactose fermentation (B): Commences immediately during milk coagulation and curd acidification, exhausting residual lactose within the first 24 to 72 hours of manufacturing (shortest time).
• Free fatty acid production (C): Moderate lipolysis by native milk lipases and starter esterases begins during initial salting and the early weeks of curing.
• Proteolysis (A): Progressive breakdown of intact caseins into high- and medium-molecular-weight peptides by chymosin, plasmin, and starter intracellular peptidases occurs over several weeks to months of primary maturation.
• Alcohol production (D): Secondary catabolism involving amino acid decarboxylation, transamination, and reduction to volatile higher alcohols (e.g., phenethyl alcohol, 3-methylbutanol) occurs during prolonged curing and late-stage aging.

Blue Stilton is an English semi-hard blue-veined cheese. It is pierced with stainless steel needles to create channels for air entry, allowing the internal growth of Penicillium roqueforti mold spores throughout the curd matrix. Hence, it is classified as an internally mold-ripened (or blue-veined) cheese.

Option analysis:

• Unripened cheese variety: Incorrect. Examples include Cottage cheese and Mozzarella.
• Internal mold ripened cheese variety: Correct. Blue Stilton is ripened from within by the internal mycelial growth of Penicillium roqueforti.
• Bacterial surface ripened cheese variety: Incorrect. Examples include Limburger and Tilsit.
• Ripened skim milk cheese variety: Incorrect.