Читать книгу Analytical Food Microbiology - Ahmed E. Yousef - Страница 49

1 How similar or different is the sample preparation scheme you wrote from the one you executed? If you encountered irregularities, how do you plan to overcome these in future laboratory exercises?

2 A batch of alfalfa sprouts was produced by company A and temporarily stored in a walk‐in refrigerator before shipping to a retail grocery store (company B). The lot is made of 1500 cardboard packages, each containing 250 g of sprouts. The criterion for acceptance or rejection of the sprouts by company B is based on the percentage of packages positive for coliforms. Company A claims their shipments will have no more than 5% of the packages positive for coliforms, and company B decided to reject any shipment when 10% (or more) of its packages are positive for coliforms. You were asked to develop a sampling plan, analyze the lot, and determine statistically if it will be accepted or rejected. To assist in developing this plan, answer the following:Determine the number of samples that should be analyzed to produce 80% statistical power.Determine the number of samples that should be analyzed to produce only 50% statistical power.Considering the large number of samples that needs to be analyzed, what could you do to decrease the number of samples analyzed yet still produce meaningful results that help company B accept or reject the lot?