Question

Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be least effective at inhibiting bacterial growth?

A) Refrigeration: slows bacterial metabolism and growth.
B) Closing previously opened containers: prevents more bacteria from entering, and excludes O₂.
C) Pickling: creates a pH at which most bacterial enzymes cannot function.
D) Canning in heavy sugar syrup: creates osmotic conditions that remove water from most bacterial cells.
E) Irradiation: kills bacteria by mutating their DNA to such an extent that their DNA-repair enzymes are overwhelmed.

Answer 1

When comparing the effectiveness of different methods to inhibit bacterial growth among the given options, option B, closing previously opened containers, should be the least effective at inhibiting bacterial growth.

Step-by-step explanation:

Closing previously opened containers is the least effective method at inhibiting bacterial growth compared to the other options because it does not change conditions that significantly affect bacterial metabolism and survival.

This method only prevents additional bacteria from entering the container and reduces the oxygen inside; it does not actively kill existing bacteria or create an environment that is significantly hostile to bacterial survival. Unlike the other methods, which involve refrigeration, pickling, sugar concentration, and irradiation, simply closing a container does not drastically change the conditions that affect bacterial metabolism and survival.

Answer 2

Answer: B) Closing previously opened containers: prevents more bacteria from entering, and excludes O₂.

Step-by-step explanation:

The bacteria are small prokaryotic single celled organisms which are abundantly available on air, water and soil. They live in water, air, soil, inside and outside the body of other organisms in symbiotic or parasitic association. These bacteria particularly invades the food items. The refrigeration, pickling, canning in heavy sugar syrup and irradiation with the radiation all can help in inhibiting the growth of the bacteria.

But closing the cans is the least effective approach as the food is already subjected to the bacterial infection which can contaminate the entire food.