Course:FNH200/Projects/2026/Group 7 Exam Question

A student wants to share practical, scientifically grounded food-safety guidelines with their friends. Which of the following home food-handling or preservation guidelines is scientifically accurate?

A) Freezing leftovers at or below -18°C sterilizes food by destroying vegetative cells and dormant bacterial spores.

B) When canning low-acid foods (pH > 4.6) at home, a boiling-water bath is insufficient because Clostridium botulinum spores can survive boiling and later germinate under favourable anaerobic conditions; pressure canning is required.

C) If a soft or porous food develops visible mould, removing the visibly mouldy portion makes the remaining food safe because fungal growth and its metabolites remain confined to the visible area.

D) A package of individually quick-frozen (IQF) vegetables that has formed a solid, icy block indicates successful maintenance of the frozen product without thawing or temperature fluctuation

Explantation: B - Low-acid foods have a pH greater than 4.6 (Lesson 2). While boiling water (100°C) kills vegetative cells, heat-resistant Clostridium botulinum spores survive 100°C moist heat and will germinate, grow, and release lethal neurotoxins in the oxygen-free environment of a canned jar (Lesson 5; Lesson 6). Safely destroying these spores requires a 12D thermal process (“botulinum cook”) at 121°C under pressure (Lesson 5; Lesson 6). This question should be included on the final exam because it applies food preservation and microbial safety concepts to a practical situation students may encounter outside the classroom. It tests whether students can distinguish between methods that simply inhibit microbial growth and those required to control heat-resistant spores, making it useful food-safety knowledge that can also be shared with others.