Ain Fikri's e-Portfolio

SCIENTIFIC CONCEPT

The activities of microorganisms direct the acidification of milk. Acidification is a process of lowering the pH of milk. Two main groups of bacteria in the milk are lactic acid bacteria and coliforms. Both of them undergo anaerobes with an optimum growth at 37˚C. They can cause rapid spoilage of milk because they are able to ferment lactose with the production of acid and gas, and are able to degrade milk proteins.

UNIQUE FEATURE OF THIS ACTIVITY

• The data will be displayed in a systematic manner, saving time in drawing graph, show relationship between values of pH with time.
• By using spreadsheet, the experimental data and graph that obtain from the experiment were recorded.
• Powerful software tool enables a fast and vivid look at the data from the experiment.
• Optional viewing of the results in real-time or post experiment.

ENGAGE

One day, Miss Kim brought some dairy milk at pekan Tanjong Malim. She only drinks half of the milk and plan to drink it again on tomorrow morning. She does not have a refrigerator at home because she can’t afford to buy one. Due to the reason, she just put the half-drink milk on dining table. On the next day, she drank the milk and went to the class. On the class, she had a stomached.

Miss Kim milk’s on the dining table.

In your opinion what had happen to Miss Kim?

Explain and give your reasons.

EMPOWER

Equipment

A Water bath

A pH electrode

A discovery

Equipment Setup Procedure:-

1. The Discovery was connected to the serial port of the computer.
2. The Discovery was turn on.
3. The pH electrode was connected to the I/O port of the Discovery.
4. The equipment was assembled.
5. The Discovery operation was started.
6. The Discovery was set up. The Discovery can be set up either by using the Discovery keypad or using the Control Panel dialog box from the Discover IT software.

Experimental Procedure:-

1. 10 ml of pasteurized milk was warmed and it was brought to room temperature.
2. Then, the milk in test tube was placed into the water bath( 37⁰C)
3. A pH electrode was inserted in the milk and screws the covering cork gently, in order to prevent any damage to the pH cable by pressing it with the cork.
4. The Discovery IT was started.
5. After 30 hours of incubation, data logging was stopped.
6. The graph and result obtained.

ENHANCE

    Milk on dining table                                                        Milk in the refrigerator

THINGS TO PONDER

1. From the situation above, which milk will cannot drink first?
2. Why?
3. Explain your answer.

ANSWER

1. Milk on dining table.
2. Because it is in optimum temperature, 37˚C that bacteria growth.
3. They can cause rapid spoilage of milk because they are able to ferment lactose with the production of acid and gas, and are able to degrade milk proteins.