BIOL202 Week 8 Lab 8; Food Microbiology

Lab 8: Food Microbiology (100 points)  Each question on the lab worksheet must be answered completely, thoroughly, in complete sentences and correctly in order to be considered for full credit  If the question asks you to do research or find a source, a reputable, credible and/or scholarly source citation must be included in order to be considered for full credit  If a math formula is required to arrive to an answer, work must be shown otherwise, no credit will be awarded Pre-Lab Questions 1. What is the “danger zone” of bacterial growth that consumers are warned against about holding foods? (5 points) 2. There are several foods and beverages listed in this lab that are created through the actions of microorganisms. Name five of the foods and the specific microorganisms that are used to make each of them. (5 points) 3. Using an online research tool such as the A-Z index on the CDC website, explain why Listeria monocytogenes is a major threat to pregnant women and their developing fetuses, who are ten times more likely to get sick than other demographic groups. (5 points) Experiment 1 Results Tables  Table 1: Time Required for Methylene Blue Color Change (10 points) Experiment 1 Post-Lab Questions 1. Which sample took the least time to become white? Why do you think this was the case? (5 points) 2. Which sample took the most time to become white? Why do you think this was the case? (10 points) 3. How does refrigeration affect the number of bacteria present in milk? (10 points) 4. How does pasteurization affect the number of bacteria present in milk? What differences would this assay show if performed using raw (unpasteurized) milk? (10 points) 5. What differences would this assay show if performed using milk that was past its expiration date and had an off-putting odor? (10 points) Experiment 2 Results Table  Table 2: Yogurt pH Results (10 points) Experiment 2 Post-Lab Questions 1. Make a graph of the pH changes over the course of the experiment. How does the pH change at each step? Why? (10 Points) 2. How does the consistency of the milk change during the production of yogurt? What facilitates this change? Is this related to the breakdown products of lactose and what about the taste? (10 points)