A thermal process is being used to reduce the microbial population on product contact surfaces of the packages
needed for aseptic packaging of the liquid product. The spoilage microorganism has a D ₁₂₁ = 10 min and a z = 8°C. The microbial population on the surface is 100 per cm ² and the product contact surface area is 8 cm ² for each package. A 9D process has been recommended.

a. Determine the process time for the containers at 140°C.

b. Estimate the number of containers with spoilage based on survivors on the package surface when 10 million packages have been filled.