Dye Reduction Method to Classify Raw and Determine Shelf-Life of Pasteurized Milk

Only available on StudyMode
  • Topic: Milk, Pasteurization, Raw milk
  • Pages : 3 (497 words )
  • Download(s) : 275
  • Published : March 7, 2013
Open Document
Text Preview
EXERCISE 3
Dye Reduction Method to Classify Raw and Determine Shelf-life of Pasteurized Milk

I. OBJECTIVES

By the end of the exercise, the student should be able to:
a. To determine and test the quality of milk samples;
b. To determine the grade of the raw milk sample;
c. To know the shelf-life of the milk sample and the efficiency of pasteurization.

II. DATA

Table 3.1. Observations on the test of raw milk sample using Resazurin Reduction Test for 3-hours at 1-hour interval.

TIMEOBSERVATIONDISCOLORATION
1st hour
2nd hour
3rd hour

Table 3.2. Observations on the test of raw milk sample using Methylene Blue Reduction Test for 3-hours at 30-minute interval.

TIMEOBSERVATIONS FOR 3 TUBES
2:30Purple (no color change)
3:00Purple (no color change)
3:30Purple (no color change)
4:00Purple (no color change)
4:30Purple (no color change)
5:00Purple (no color change)
5:30Purple (no color change)
6:00Purple (no color change)

Table 3.3. Observations on the color changes of pasteurized milk samples subjected to Resazurin Reduction Test incubated at 7.20C for 7 days.

DATEOBSERVATIONS
COW HEADMAGNOLIA FRESH MILK
1st tube2nd tube1st tube2nd tube
December 15Blue - ExcellentBlue - ExcellentBlue - ExcellentBlue - Excellent December 16Blue - ExcellentBlue - ExcellentBlue - ExcellentBlue - Excellent December 17Blue - ExcellentBlue - ExcellentBlue - ExcellentBlue - Excellent December 18Blue - ExcellentBlue - ExcellentBlue - ExcellentBlue - Excellent December 19Blue - ExcellentBlue - ExcellentBlue - ExcellentBlue - Excellent December 20Blue - ExcellentBlue - ExcellentBlue - ExcellentBlue - Excellent December 21Blue - ExcellentBlue - ExcellentBlue - ExcellentBlue - Excellent

III. ANSWERS TO QUESTIONS

1. What is the function of resazurin in the reduction test and what type of chemical reaction is involved?

Resazurin is a blue crystalline dye C12H7NO4 that is an indicator...
tracking img