Which sign of spoilage is related to gas production?

• A. Off-odours
• B. Discolouration
• C. The production of gas
• D. Mould growth

Answer: (C)

Gas production is a telltale sign that microbes are metabolizing in the food and releasing gases such as carbon dioxide. In packaged foods, this often shows up as swollen or bulging packaging, bubbles, or foaming, which directly points to gas formation as part of spoilage. That makes it the best marker among the options for gas-related spoilage.

Off-odours, discolouration, and mould growth are also signs of spoilage, but they describe other changes (volatile compounds, pigment changes, and fungal growth) rather than the specific production of gas.