if milk goes off in 1 day,at 24 degrees Celsius how long will it last at 4 degrees celsius?

Question

basic pinciple and calculations.

Answer 1

The real answer is that there is almost no way to tell. But if you like, we can make a number of erroneous assumptions about what is happening and come up with completely unreal answers.

I can't help but notice you've posted this in the chemistry section, for example. So, if you like, we could assume that this change in the milk is a chemical one. The formula most closely involved would be the Arrhenius equation. This states that the rate of the reaction is proportial to the temperature. To be precise:

k = Ae^(-Ea/RT)

Since everything else stays the same, we can see that the rate changes by a factor of e^(1/T), which would produce a miniscule difference of less than a tenth of a percent. The reason it's so small is because the temperature has to be stated in kelvin for the equation, so it's only a 10% difference to start with and gets smaller from there. So, making these erroneous assumptions, we can say that at 4 degrees C it will still spoil in 1 day.

What REALLY causes milk to spoil is the activity of bacteria which produce lactic acid. If your milk was pasteurized by ultra-high-temperature treatment, then it could be stored at room temperature for months without spoiling, but depending on the environment might still spoil in a day once opened. In this case, the temperature difference might or might not make a huge difference depending on which bacterium exactly was doing the spoiling.

In completely unpasteurized milk, the intrinsic bacteria makes it sour quickly, but it's actually still safe to drink because those bacteria are not themselves dangerous and the sourness prevents other bacteria from surviving in it. So it sours quickly (in about five days), but is consumable longer, comparatively.

Most milk is imperfectly pasteurized so you end up with results somewhere in between. Which is why nobody can tell you, probably - it depends too much on environmental conditions other than the temperature. The typical dairy will say that the shelf life of milk, if properly stored just above freezing all the time, is a couple of weeks from the date when it is produced.

Answer 2

1day = 24 degC

4degsC x 1day/24degC = .17 day

1day = 24 hrs

.17day x 24hrs/1day = 4.08 hrs

4 hrs

Answer 3

6 hrs ?