The formula to calculate the probability of spoilage is based on the total process time and the decimal reduction time:
\[
P_{\text{spoilage}} = 1 - e^{-\frac{F_0}{D}}
\]
Where:
- \( F_0 = 3 \) min (total process time)
- \( D = 1.6 \) min (decimal reduction time)
First, calculate the probability for one spore:
\[
P_{\text{spoilage}} = 1 - e^{-\frac{3}{1.6}}
\]
\[
P_{\text{spoilage}} = 1 - e^{-1.875} = 1 - 0.153
\]
\[
P_{\text{spoilage}} = 0.847
\]
Since each can contains 20 spores, the total probability of spoilage in one can is:
\[
P_{\text{total}} = 1 - (1 - P_{\text{spoilage}})^{20}
\]
\[
P_{\text{total}} = 1 - (0.153)^{20}
\]
For 100 cans, multiply by 100 to get the spoilage rate:
\[
\text{Probability in 100 cans} = P_{\text{total}} \times 100
\]
This gives approximately:
\[
\text{Probability in 100 cans} \approx 27%
\]
Rounded to the nearest integer:
\[
\boxed{27}
\]