CSS - PMS - CCE - PCS - General Science
Applied Chemistry - Food Preservatives
Which statement best distinguishes a preservative from a flavoring agent?
A. A preservative only changes food color
B. A preservative is added mainly to delay spoilage or microbial growth
C. A preservative must always make food sweeter
D. A preservative always increases protein content
Correct Answer: B
Preservatives are used primarily to extend shelf life by slowing chemical or microbial deterioration.
CSS - PMS - CCE - PCS - General Science
Applied Chemistry - Food Preservatives
Sulfur dioxide is especially associated with preserving which type of food?
A. Dried fruits and some fruit products
B. Cooking oil only
C. Fresh milk only
D. Raw eggs only
Correct Answer: A
Sulfur dioxide and sulfites are used to control browning and microbial spoilage in some dried fruits and beverages.
CSS - PMS - CCE - PCS - General Science
Applied Chemistry - Food Preservatives
Which method preserves food mainly by removing moisture?
A. Dehydration
B. Electrolysis
C. Neutralization
D. Hydrogenation
Correct Answer: A
Drying or dehydration lowers water activity, limiting microbial growth and enzymatic spoilage.
CSS - PMS - CCE - PCS - General Science
Applied Chemistry - Food Preservatives
Which natural acid is traditionally important in pickling for preservation?
A. Sulfuric acid
B. Acetic acid
C. Nitric acid
D. Hydrochloric acid
Correct Answer: B
Vinegar contains acetic acid, which lowers pH and inhibits many microorganisms.
CSS - PMS - CCE - PCS - General Science
Applied Chemistry - Food Preservatives
What is pasteurization primarily designed to do?
A. Freeze all microorganisms permanently
B. Increase food acidity to pH 1
C. Reduce pathogenic and spoilage microorganisms by controlled heating
D. Remove all water from food
Correct Answer: C
Pasteurization uses controlled heat to reduce pathogens and spoilage organisms without fully sterilizing the food.
CSS - PMS - CCE - PCS - General Science
Applied Chemistry - Food Preservatives
Which gas is used in modified-atmosphere packaging to slow oxidation and microbial growth?
A. Chlorine
B. Hydrogen
C. Carbon dioxide
D. Helium
Correct Answer: C
Carbon dioxide can suppress growth of many spoilage organisms and is used in food packaging.
CSS - PMS - CCE - PCS - General Science
Applied Chemistry - Food Preservatives
Why does sugar help preserve jams and jellies?
A. Sugar sterilizes food by radiation
B. Sugar converts microbes into acids
C. Sugar removes all minerals
D. High sugar concentration reduces water available to microorganisms
Correct Answer: D
Concentrated sugar binds water and produces osmotic conditions unfavorable to many microbes.
CSS - PMS - CCE - PCS - General Science
Applied Chemistry - Food Preservatives
What is the main preservative action of common salt in food?
A. It lowers water activity by drawing water out of microbial cells
B. It increases food pH sharply
C. It supplies oxygen to microbes
D. It converts fats into proteins
Correct Answer: A
High salt concentration reduces available water and creates osmotic stress for microorganisms.
CSS - PMS - CCE - PCS - General Science
Applied Chemistry - Food Preservatives
Which preservative is widely used in jams and fruit products to inhibit molds and yeasts?
A. Potassium nitrate
B. Calcium oxide
C. Sodium bicarbonate
D. Potassium sorbate
Correct Answer: D
Potassium sorbate is effective against molds and yeasts and is commonly used in fruit products.
CSS - PMS - CCE - PCS - General Science
Applied Chemistry - Food Preservatives
Which substance is commonly used as a preservative in acidic foods and soft drinks?
A. Sodium benzoate
B. Magnesium sulfate
C. Calcium carbonate
D. Sodium chloride only
Correct Answer: A
Sodium benzoate inhibits growth of yeasts, molds and some bacteria, especially in acidic foods.