What does checking expiry dates primarily prevent, and what is a key characteristic of enzymes?

Step 1: Analyze Question 39. The question asks what checking expiry dates before purchase mainly protects against. Expired food can be spoiled and contain harmful microorganisms or toxins, leading to food-borne illness. A) Food adulteration refers to adding inferior substances to food. B) Food security refers to access to sufficient, safe, and nutritious food. C) Price inflation is an economic concept. D) Food-borne illness is directly caused by consuming unsafe food, which expired food often is. The correct answer is food-borne illness. Answer:* D Step 2: Analyze Question 40. The question asks which option specifically describes enzymes. A) Lipase acting on fats only describes the specificity* of enzymes, meaning each enzyme typically acts on a particular substrate or type of substrate. This is a defining characteristic of enzymes. B) Heat generally denatures and kills* enzymes, but this isn't a description of their active state. C) Acids can denature enzymes, but "lowly reacting" is vague and not a specific description of enzymes. D) Enzymes are biological catalysts and, like all catalysts, are reused in reactions. While true, their high degree of specificity* is a more distinguishing characteristic among catalysts. The most specific description among the options, highlighting a unique property of enzymes, is their specificity of action. Answer:* A Step 3: Analyze Question 41. The question asks which observation would likely indicate spoilage in packaged meat. A) Firm texture is generally a sign of fresh meat. B) Normal smell indicates freshness. C) Cold from freezer indicates proper storage. D) Greenish colour* is a common visual sign of meat spoilage, often due to microbial growth. The correct answer is greenish colour. Answer:* D Step 4: Analyze Question 42. The question asks which setup best prevents cross-contamination. Cross-contamination is the transfer of harmful bacteria from one food item (often raw) to another (often cooked or ready-to-eat). A) Storing all food together increases the risk of cross-contamination. B) Using separate cutting boards and utensils* for different types of food (e.g., raw meat and vegetables) is a key practice to prevent cross-contamination. C) Washing hands occasionally is insufficient; hands should be washed frequently and thoroughly. D) Cooking food at room temperature promotes bacterial growth and increases risk, rather than preventing cross-contamination. The correct answer is using separate cutting boards and utensils. Answer:* B Step 5: Analyze Question 43. The question asks about the use of coagulation during water treatment. Coagulation is a process in water treatment where chemicals (coagulants) are added to water to neutralize the electrical charges of suspended particles. This causes the particles to come together. C) These smaller particles then clump together into larger, heavier flocs* (flocculation), which can then be easily removed by sedimentation or filtration. A) Coagulation primarily removes particles, not directly kills microorganisms, although some may be trapped in flocs. B) It does not remove dissolved salts. D) It does not directly improve water hardness (which is due to dissolved minerals). The correct answer is to clump fine particles into large flocs. Answer:* C Step 6: Analyze Question 44. The question asks which beverage best demonstrates a natural non-alcoholic drink. A) Beer is an alcoholic beverage. B) Juice is a general category, some of which can be natural and non-alcoholic. C) Fresh orange juice* is a specific example of a natural beverage that is non-alcoholic. D) Brandy is an alcoholic beverage. Fresh orange juice is the most specific and accurate example among the options. Answer:* C Step 7: Analyze Question 45. The question asks which event occurs first during digestion after food enters the mouth. Digestion begins in the mouth. B) The very first process is mechanical breakdown* (chewing or mastication), which physically breaks down food into smaller pieces. A) Protein hydrolysis (breakdown) primarily begins in the stomach. C) Fat emulsification primarily occurs in the small intestine. D) Absorption of glucose primarily occurs in the small intestine. The correct answer is mechanical breakdown. Answer:* B