# How long will the milk remain unspoiled at 20C?

Asked by sillymichelleyoung (217) February 2nd, 2013

Hello,

I have a question that I need to do for homework that I can not figure out how to do.

The contents will spoil in 8 days if stored at 5C. The contents will spoil in 12 hours if stored at 30C. If the mechanism and definition of spoilage remain constant in this temperature range, how long will the milk remain unspoiled at 20C?

I’m not looking for the answer, I want to know how to do the problem. The answer is 34.4 hours, but I can’t figure out how to start. I know it has to do with kinetics and reaction rate, but how do I approach this problem? How do I find the reaction rate in relation to temperature?

Thank you!

Observing members: 0 Composing members: 0

I don’t know what course you are taking, but spoilage is not on a constant rate of temperature and time. All I know is milk goes sour in ½ half day at room temperature. 20 C is room temperature.

zenvelo (30407)

Consider “time until spoilage” (measured in hours) on one axis of a flat X-Y graph and “storage temperature” (measured in °C) on the other axis.

Graph your two points.

Assuming a straight line between those points (okay, “line segment”), regardless of others’ advice on the topic of milk spoilage, the point you’re looking for should be a point on that line. You can do it by calculating, based on the formulas for line slope, one of the starting points, and the given temperature of 20°C, or you can attempt to eyeball the line at the point of the 20°C intercept.

Does that help?

CWOTUS (24778)

(^^^It sure helped me.)

gailcalled (54405)

Depends on how the milk was processed before being filled for sale.

mattbrowne (31545)

Layout the problem as CWOTUS suggested. Then use the Properties of Similar Triangles, where corresponding sides are all in the same proportion.

bossob (5899)
Response moderated (Writing Standards)

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