In order to establish the expiration date of perishable food, growth curve data must be collected. Once the microbial load is so high that it poses a hazard to human health, the food item is no longer considered safe (expired). Generally a microbial load of x50,000 bacteria/gram is considered unsafe. Your task is to determine the microbial growth curves for MicroYo, a new brand of yogurt. The growth is determined by sampling the yogurt and growing the bacterial isolates in broth culture which is then serially diluted by a total of x10,000 and inoculated onto standard petri plates of nutrient agar. The following colony counts are measured:
Time (days) MicroYo colony count
1 1
4 1
12 2
16 4
20 7
a. 4.
b. 16.
c. 20.
d. 12.