A student investigated the effect of temperature on the rate of decay of three different types of milk (cows' milk, soy milk, and oat milk) by measuring the time taken for the pH to decrease to 4.5. The results are shown in the graph below.
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Which type of milk stays fresh the longest at 10 ∘C^\circ\text{C}∘C?
Describe the effect of temperature on the time taken for soy milk to reach pH 4.5. Use values from the graph in your answer.
Suggest one reason why cows' milk decays faster at 15 ∘C^\circ\text{C}∘C than at 5 ∘C^\circ\text{C}∘C.