Lab 6 for Microbiology Lab from Straighterline

lOMoARcPSD| Lab 6 for Microbiology Lab from Straighterline Fundmtls Of Microbiology W Lab lOMoARcPSD| Lab 6 Food Microbiology BIO250L” Student Name: Access Code (located on the underside of the lid of your lab kit): “Pre-Lab Questions” 1. Escherichia coli is one of the most common causes of food-borne illness, yet it is also a common microorganism found within the human gut. What explains this disparity? E. coli illnesses contain certain factors that can be considered as foreign structures. These factors cause infection to the host. 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. Cheese: lactococcus, yogurt: lactobacillus, fruit: E. Coli, bread: saccharomyces, milk: listeria monocytogenes 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. This is a major threat to pregnant women because this can get through to the placenta, overall harming the fetus. It can result in serious outcomes such as miscarriage, still birth, and maternal and neonatal sepsis. “EXPERIMENT 1: Assessing the Bacterial Load of Milk with Methylene Blue RESULTS TABLES Table 1: Time Required for Methylene Blue Color Change Milk Sample Start Time/Date End Time/Date Time Elapsed (Step 10) (Step 11) (End Time-Start Time) 0 hours 1pm 1pm 5 min 1 hour 12pm 1pm 1 hour 3 hours 10am 1pm 3 hours lOMoARcPSD| Lab 6 Food Microbiology BIO250L” Milk Sample Start Time/Date End Time/Date Time Elapsed (Step 10) (Step 11) (End Time-Start Time) 4 hours 9am 1pm 4 hours POST-LAB QUESTIONS 1. On average, which sample took the least time to become white? Why do you think this was the case? The four hour sample because it was at room temperature. 2. On average, which sample took the most time to become white? Why do you think this was the case? The zero hour sample. 3. How does refrigeration affect the number of bacteria present in milk? The refrigeration had a lower number of bacteria present. Bacteria does not thrive in colder temperatures. 4. How does pasteurization affect the number of bacteria present in milk? Pasteurized milk destroys pathogenic bacteria so there is not much bacteria present. 5. What differences, if any, would this assay show if performed using raw (unpasteurized) milk? The color of the milk would changer quicker. 6. What differences, if any, would this assay show if performed using milk that was past its expiration date and had an off-putting odor? More bacteria would be present so the color would change more quickly. lOMoARcPSD| Lab 6 Food Microbiology BIO250L” Insert a photo of your tubes. Include your name and access code handwritten in the background of your photo. Hour 0 compared to Hour 4 “EXPERIMENT 2: Yogurt Preparation DATA TABLES Table 2: Yogurt pH Results Sample (Step #) pH 2 7 6 7 10 6 14 5 15 4 POST-LAB QUESTIONS 1. Make a graph of the pH changes over the course of the experiment. Insert it below. How does the pH change at each step? Why? WHen the milk was warmed and cooled, the bacteria converted from lactose to lactic acid, making it more acidic. lOMoARcPSD| Lab 6 Food Microbiology BIO250L” 2. What attributes does lactic acid confer to yogurt? Lactic acid helps yogurt have that soft and creamy texture and the taste. 3. How does the consistency of the milk change during the production of yogurt? What facilitates this change? Milk thickens because the lactic acid is being added during the production of the yogurt. 4. What are the breakdown products of lactose? Galactose and glucose are the breakdown products. Insert a photo of your pH strips. Include your name and access code handwritten in the background of your photo. MoARcPSD| Lab 6 Food Microbiology BIO250L”