1. Which component makes up the largest percentage of whole cow’s milk by mass?
- A.A) Fat
- B.B) Protein
- C.C) Water
- D.D) Lactose
Food Science Practice Test — Easy Level
A free 10-question Food Science practice test for Science Olympiad, written at invitational level. Every question and answer choice is listed below — correct answers and scoring are revealed when you take the timed test.
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2. In cow’s milk, which carbohydrate is present in the highest amount and is specifically broken down by the enzyme lactase?
- A.A) Sucrose
- B.B) Lactose
- C.C) Glucose
- D.D) Maltose
3. Casein molecules in milk are organized into structures called micelles. Which of the following best describes what happens to these casein micelles when the pH is lowered to about 4.6 using an acid in a curd mass lab?
- A.A) They gain more negative charge and stay evenly dispersed
- B.B) They reach their isoelectric point and clump together to form curds
- C.C) They dissolve completely to form a true solution
- D.D) They are broken down into amino acids by hydrolysis
4. During ice cream making with ice and salt, why is salt added to the ice surrounding the ice cream mix?
- A.A) To raise the freezing point so the ice stays frozen longer
- B.B) To lower the freezing point so the brine becomes colder than 0 °C
- C.C) To supply extra sodium for flavor in the ice cream mix
- D.D) To absorb heat directly from the ice cream without melting the ice
5. Which statement correctly compares saturated and unsaturated fatty acids commonly found in milk fat?
- A.A) Saturated fatty acids contain no double bonds and are usually solid at room temperature
- B.B) Saturated fatty acids contain multiple double bonds and are usually liquid at room temperature
- C.C) Unsaturated fatty acids contain no double bonds and are usually solid at room temperature
- D.D) Unsaturated fatty acids always have exactly one double bond and are usually solid at room temperature
6. A student with lactose intolerance drinks a glass of regular cow’s milk and later experiences gas and cramps. Which best explains the cause of these symptoms?
- A.A) Their immune system produced IgE antibodies against casein
- B.B) Their body lacks enough lactase to digest lactose in the small intestine
- C.C) Their pancreas overproduced insulin in response to milk sugar
- D.D) Their stomach acid denatured all the milk proteins too quickly
7. Which pair of microorganisms is used as the standard starter culture for traditional yogurt production?
- A.A) Lactococcus lactis and Leuconostoc mesenteroides
- B.B) Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus
- C.C) Saccharomyces cerevisiae and Lactobacillus plantarum
- D.D) Escherichia coli and Streptococcus pyogenes
8. Pasteurized, homogenized whole milk is described as three types of mixtures at once. Which component of milk is correctly matched to the type of mixture it forms?
- A.A) Fat globules – true solution
- B.B) Lactose – colloidal dispersion
- C.C) Casein micelles – colloidal dispersion
- D.D) Minerals – emulsion
9. Which preservation or processing step is specifically designed to kill pathogenic microorganisms in milk?
- A.A) Homogenization at high pressure
- B.B) Pasteurization at controlled time and temperature
- C.C) Standardization of fat content using the Pearson square
- D.D) Fortification with vitamin D
10. During cream churning in a butter lab, what physical change in the fat globules is most directly responsible for the formation of butter grains?
- A.A) The fat globules dissolve to form a true solution with water
- B.B) The fat globule membranes break and fat partially coalesces into larger clumps
- C.C) The fat globules crystallize into ice at 0 °C
- D.D) The fat globules are converted into lactose and proteins