Food Science Quiz 14
What this quiz covers
Milk looks simple and behaves like anything but. Heat it a fraction too cool and pathogens survive; heat it a fraction too long and the flavor dies. The entire dairy industry lives inside that narrow window, which is why this quiz spends so much time there: the exact time and temperature of HTST pasteurization, the phosphatase test that proves the process worked, the boiling point of milk down to the decimal. These are not numbers you look up on the line — they are numbers a QA technician is expected to know cold, because a pasteurizer does not wait for anyone to check a reference.
The twenty questions sweep from physics to biology: ohmic heating and its two names, the frequencies microwaves actually use, visible light’s wavelength band, papain and bromelain tenderizing meat, insulin’s job, which vitamin doubles as an antioxidant, why nisin counts as natural, what calcium propionate does in a cake, how rennet and recombinant chymosin both end up making cheese, and the full roster of hurdles — temperature, water activity, redox potential — in hurdle technology. It closes with sauerkraut and the lactic acid bacteria that make it safe.
Heat, then microbes, then the combination
Read the quiz in three blocks. First, heat as a tool: ohmic heating, microwave frequencies, HTST conditions, the phosphatase check. Second, ingredients with a job: nisin against bacteria, propionates against mold, enzymes against tough meat. Third, the living processes — cheese, sauerkraut, and hurdle technology, which is really the philosophy tying everything together: no single barrier has to do all the work if several small ones stack up. That idea, more than any single number, is what the best questions here are testing.
How to use this quiz
You get 20 seconds per question and one attempt at each answer. The dairy numbers — 71.7°C for 15 seconds, the phosphatase test, what UHT demands — are worth drilling until they are automatic, because they recur in every food-safety exam on the planet. For the microbe questions, learn the organism’s job: what Leuconostoc makes, what nisin kills, why hurdle technology works. Then retake the quiz and watch the score move.
Answer explanations
Worked through the quiz? Here is why each correct answer is correct — the concept behind it, in plain terms.
- Ohmic heating is also known as
Correct answer: both — Ohmic heating passes electric current directly through the food, so it is simultaneously Joule heating and electrical resistance heating — the food itself is the resistor. - Hormone controlling blood sugar levels is
Correct answer: insulin — Insulin, from the pancreatic beta cells, drives glucose into cells and lowers blood sugar; its failure or resistance defines diabetes mellitus. - Electromagnetic radiation in the range of wavelengths 400-700 nm is called
Correct answer: visible light — The human eye sees roughly 400–700 nm; below that band is UV, above it infrared. - Frequency used in microwave heating is
Correct answer: both — Food microwave systems are assigned 915 MHz (industrial) and 2450 MHz (domestic) — both bands are in real use. - Which of the following is meat tenderizer enzyme
Correct answer: both — Papain (papaya) and bromelain (pineapple) are both plant proteases that break down muscle proteins — the classic natural tenderizers. - Which of the following is most important for the success of a new food product in the market?
Correct answer: sensory — Consumers buy with their senses: if the flavor, texture, and appearance don’t win, composition and marketing can’t save the product. - Boiling point of milk is
Correct answer: 100.07°C — Dissolved lactose and minerals elevate milk’s boiling point a touch above water’s 100°C. - Vitamin having anti-oxidant properties
Correct answer: vitamin C — Vitamin C (ascorbic acid) is a frontline water-soluble antioxidant, scavenging free radicals and regenerating vitamin E. - Which of the following is fat soluble vitamin
Correct answer: retinol — Retinol is vitamin A — fat-soluble and stored in the liver — while thiamine, riboflavin, and ascorbic acid are all water-soluble. - Which of the following is not a tetrose
Correct answer: ribose — Erythrose, threose, and erythrulose are four-carbon tetroses; ribose has five carbons — a pentose — so it is the odd one out. - Which of the following is a measure of central tendency
Correct answer: all options — Mean, median, and mode are the three classic measures of central tendency. - Which of the following natural preservative is used in various food products for increasing shelf life and inhibiting growth of bacteria
Correct answer: nisin — Nisin is a bacteriocin made by Lactococcus lactis — a natural antimicrobial that kills Gram-positive bacteria and extends shelf life. - Which of the following is used for preservation of cake and other baked products
Correct answer: both — Sorbic acid and calcium propionate are both used against mold in cakes and bread; propionates are the bakery workhorse, sorbates the broader backup. - Cheese prepared using skim milk is
Correct answer: all options — Cottage, ricotta, and parmesan can all be made from skim milk — removing the fat doesn’t remove the casein that forms the curd. - HTST pasteurization of milk is carried out at
Correct answer: 71.7°C for 15 sec — HTST (high-temperature short-time) pasteurization is defined as 71.7°C (161°F) for 15 seconds — hot enough to kill Coxiella burnetii, brief enough to protect flavor. - Phosphatase test is done to check the adequacy of
Correct answer: pasteurization — The phosphatase test checks that alkaline phosphatase — an enzyme slightly hardier than most milk pathogens — has been destroyed, proving the milk got its proper heat treatment. - Cryovac is related to
Correct answer: food packaging — Cryovac is the vacuum-shrink packaging system: film shrinks tight around meat and cheese, excluding oxygen and extending shelf life. - Cheese is the dairy product prepared with the help of
Correct answer: both — Cheese is set with traditional animal rennet or recombinant chymosin (fermentation-produced) — both supply the chymosin that coagulates casein. - The hurdle included in hurdle technology is
Correct answer: all options — Hurdle technology stacks mild barriers — temperature, water activity, redox potential, pH, preservatives — so no single harsh treatment is needed. - Leuconostoc mesenteroides produce _______ acid in Sauerkraut
Correct answer: lactic acid — Leuconostoc mesenteroides starts sauerkraut fermentation, converting cabbage sugars to lactic acid, which drops the pH and makes the product safe.