How can you recognize cold milk that has gone bad or is about to?
The methods that I know to test cold milk is to either boil it and look for the break, taste it (yuk!), or hope it smells bad enough to know it's bad.
Is there an easy and scientific way to know whether milk is still good? and for how much longer it's likely to stay good?
The expiry date alone is not a good indicator since it assumes some conditions about the storage temperature and we've all seen good milk past expiry and bad milk before expiry.
I'm also curious about the particular moment beyond which we consider milk 'goes bad'. Can one tell how far away it is from the current seemingly healthy condition of milk?
Best Answer
Looks like FAO (Food and Agriculture Organization of the United Nations) publishes a formal testing handbook here.
One of the easier methods:
2.4.5.3. The Alcohol Test
The test is quick and simple. It is besed on instability of the proteins when the levels of acid and/or rennet are increased and acted upon by the alcohol. Also increased levels of albumen (colostrum milk) and salt concentrates (mastitis) results in a positive test.
Procedure:
The test is done by mixing equal amounts of milk and 68% of ethanol solution in a small bottle or test tube. (68 % Ethanol solution is prepared from 68 mls 96%(absolute) alcohol and 23 mls distilled water). If the tested milk is of good quality, there will be no coagulation, clotting or precipitation, but it is necessary to look for small lumps. The first clotting due to acid development can first be seen at 0.21-0.23% Lactic acid. For routine testing 2 mls milk is mixed with 2 mls 68% alcohol.
Simplified for home use:
This test is likely to be adaptable to household alcohol drinks such as vodka or similar beverages. For example the number of teaspoons of Vodka an ounce or two of milk can hold before it clots.
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5 Ways to know if milk has gone bad / is spoiled
More answers regarding how can you recognize cold milk that has gone bad or is about to?
Answer 2
Use your nose. The smell of sour milk is overpoweringly wretched. My belief is that if you can stand to smell it, you can stand to drink it.
Answer 3
BEST WAY IS:
Pour a small amount of milk into a cup of hot water, the milk will rise/float to the top in small, thin clumps if it is bad.
The clumps are thicker as the milk spoils more.
DONE!
Answer 4
Working on a theory that milk in early stages of going bad will stick to side of glass longer than fresh milk and that residue will consist of almost micro curds if you look closely.
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