This set of Fruits Processing Multiple Choice Questions & Answers (MCQs) focuses on “Canning of Fruits”.
1. What is the pH range of low acid foods?
a) 5-6.8
b) 6.8-7
c) 8-10
d) 1-4
View Answer
Explanation: The low acid foods have a pH range of 5.0 to 6.8. Some of the examples for low acid food are meat, dairy, fish and poultry. It normally has a water activity greater than 0.85. They require higher temperature in the canning process to destroy the microbes.
2. What is the pH range of moderate acid foods?
a) 5-6.8
b) 3.7- 4.5
c) 2-4
d) 1-2
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Explanation: Moderate acid foods have pH values between 4.5 and 3.7. Some of the examples of moderate acid foods are pear, oranges, apricots and tomatoes. It does not require high temperature compared to low acids foods. The preservatives are added during the canning process.
3. What is the pH range of high acid foods?
a) 5-6.8
b) 3.7- 4.5
c) 2.3-3.7
d) 1-2
View Answer
Explanation: Generally all the pickled products and fermented foods come under high acid food category. The pH values range from 2.3 and 3.7. Jams and Jellies also called as high acid foods. It does not require very high temperature. Components like salt, sugar, citric acids that are present in the product acts as preservatives.
4. How much head space is given in canning?
a) 0.32-0.47
b) 0.5-0.67
c) 0.7-0.8
d) 0.87-0.99
View Answer
Explanation: Headspace is the distance between the surface of food and the underside of the lid. Generally the head space can ranges from 0.32 to 0.47. If too much headspace is permitted then the food at the top undergoes discoloration. If little headspace is permitted, then the food may expand and bubble out during processing.
5. Which of the following is also called as thermal exhausting?
a) Steam vacuum exhausting
b) Mechanical exhausting
c) Machine vacuum exhausting
d) High temperature exhausting
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Explanation: Exhausting is defined as the process of removal of air from cans. After filling and lidding exhausting is essential to avoid corrosion of tinplate. Thermal exhausting is done by using steam vacuum. It reduces the reaction between the product and the container.
6. Which of the following spoilage results in permanent bulging of cans at both ends?
a) Hard swell
b) Soft swell
c) Flipper
d) Springer
View Answer
Explanation: Hard swell is defined as the spoilage that results in permanent bulged on both ends of the can. The ends can’t be pressed in and causes swell in the container. This is due to production of gases like hydrogen and carbon dioxide.
7. Which of the spoilage is caused by thermophilic spore formers?
a) Flat sour spoilage
b) Sulfide spoilage
c) Hydrogen spoilage
d) Gaseous spoilage
View Answer
Explanation: The flat sour spoilage is caused by thermophilic spore formers. Some of the examples are such as Bacillus stearothermophilus and B. coagulans. In this spoilage, the can does not bulge but pH level decreases. The food tastes sour and produces off odors.
8. Which of the spoilage is caused by anaerobic thermophilic spore formers?
a) Flat sour spoilage
b) Sulfide spoilage
c) Hydrogen spoilage
d) Gaseous spoilage
View Answer
Explanation: The sulfide spoilage is caused by anaerobic thermophilic spore formers. These microbes such as Clostridium nigrificans and C. bifermentans produce hydrogen sulfide. The gas is often absorbed by the food. The can may not swell but produces off odor. Blackening of the food can also be seen.
9. Which of the spoilage is caused by putrefactive anaerobes?
a) Flat sour spoilage
b) Sulfide spoilage
c) Hydrogen spoilage
d) Gaseous spoilage
View Answer
Explanation: The gaseous spoilage is caused by putrefactive anaerobes. Example for putrefactive anaerobes is C. butyricum. The can swells up on both directions. The food can have a fermented, cheesy or putrid odor.
10. What are R- enamel cans?
a) They are acid resistant cans
b) They are sulphur resistant cans
c) They are hydrogen resistant cans
d) They are ammonium resistant cans
View Answer
Explanation: These steel cans are coated with tin on both sides of the container. Some strong acidic foods react with tin and produce a discolored product on longer exposure. So therefore to prevent the food from spoilage R-enamel is used as an enamel liner.
11. What are C- enamel cans?
a) They are acid resistant cans
b) They are sulphur resistant cans
c) They are hydrogen resistant cans
d) They are ammonium resistant cans
View Answer
Explanation: Certain food that are high in sulfur or that are close to neutral in pH will discolor from prolonged contact with tin. For those foods, cans with C-enamel are used to prevent from discoloration. They are also called as sulphur resistant cans.
Sanfoundry Global Education & Learning Series – Fruits Processing.
To practice all areas of Fruits Processing, here is complete set of 1000+ Multiple Choice Questions and Answers.
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