Question

1. Which thermal processing methods can render a commercially sterile product with least chemical damage?

a In-container sterilization using an agitating retort

b In-container sterilization in a still retort

c UHT processing using an infusion sterilizer

d UHT processing using a plate heat exchanger

2. A food processor would be satisfied with a spoilage level of one pack or less in every 10,000. If the initial population of a target spoilage organism is 100 per pack, which sterilization process is adequate?

a sterilization value = 3D (D is the decimal reduction time)

b sterilization value = 5D

c sterilization value = 6D

d sterilization value = 12D

3 Which lists processing temperature from low to high in treating liquid milk?

A. In container sterilization < Pasteurization < UHT

B. Pasteurization < UHT < In container sterilization

C. Pasteurization < In container sterilization < UHT

D. In container sterilization < UHT < Pasteurization

4

Which is Wrong about canned foods?

A. Canned food may contain a few viable spores.

B. Deterioration of canned food during storage is mainly due to chemical change.

C. Higher storage temperatures will accelerate chemical reactions.

D. Higher storage temperatures are unfavorable for the germination of thermophilic spores.

5. One of the purposes to have the soymilk thermally processed is to

A. denature the soy proteins

B. stabilize the soymilk emulsion

C. inactivate the trypsin inhibitor

D. remove the beany flavor

6

. In the production of UHT aseptically packed milk, direct UHT heating followed by evaporative cooling in a flash chamber is better than indirect UHT heating from the standpoint of

a minimizing heat damage to milk

b higher thermal efficiency

c longer shelf life

d minimizing holding time

Answer 1

Answer 1) C) UHT processing using an infusion sterilizer. Because in this process product is sterilized at ultra high Temperature for few seconds. In this product pass through steam in a vessel which does directly sterilization of product with minimal heat degradation.

2) a. Sterilization value = 3D

3) C. pasteurization= 63-70?. In hot container =121? UHT= 136?

4) D) as higher temperatures is favorable for the germination of thermophilic spores

5.B.to stabilize the soy milk emulsion which is essential for storing.

6. C. Higher thermal efficiency as in indirect UHT plates are uses which is not thermal efficient