Final answer:
The total plate count method, involving serial dilution and the spread plate technique, is used to measure bacterial contamination in processed peanut butter. The correct answer is option a).
Step-by-step explanation:
To measure the concentration of bacterial contamination in processed peanut butter, the total plate count method would be used. This method involves using a serial dilution process to dilute the peanut butter sample, which is then spread onto solid agar plates through the spread plate method.
After incubation, bacterial colonies that grow on the agar are counted, providing an estimate of the number of bacteria in the original sample. The total plate count is a direct method of measuring bacterial growth, which allows for the counting of viable bacteria in a sample.
It's considered more reliable than indirect methods, such as spectrophotometry, because it provides a count of live bacteria that are capable of reproduction. For food safety and quality control, it is essential to determine the actual number of living bacteria to assess the level of contamination accurately.