FOOD3230 Lab Report 1 (6)

What advantage does the oil immersion objective have over the low power objective when doing bacterial examination?

answer the following questions with book reference. 1. What is meant by a bacterial “colony” or colony-forming unit? 2. Why are colonies that develop on a heavily seeded plate smaller than those that appear on a sparely seeded plate? 3. What are some of the uses and advantages of the ff.:a. Agar plateb. Agar slantc. Broth culture 4. What are the advantages and limitations of studying bacteria by means of the Culture method? 5. Why is it desirable that most cultures be inspected after 15 to 18 hours of incubation? 6. Why should culture media after inoculation be incubated at an optimal temperature immediately? 7. Describe other types of aerobic jars and anaerobic methods.

Given the illustration and values below, determine the concentration of the original sample. Report results in CFU/mL or colony-forming unit/milliliter. Note that in order to observe the accuracy of results, culture plates with countable colonies between 25-250 CFU are considered in standard bacterial plate count.

Out of the three gram-positive bacteria (Micrococcus luteus, Staphylococcus aureus, and Staphylococcus epidermidis).  Which of the following test(s) will help me identify the unknown gram-positive bacteria?     Gram Stain Wet Mount (motility testing) Endospore Staining Acid Fast Staining Differential & Selective Media (MacConkey, PEA, EMB, MSA Agar, Blood Agar, etc.) Oxidative-Fermentative Test Carbohydrate Fermentation MR-VP Testing Indole Production Citrate Utilization Triple Sugar Iron Testing Catalase Test

A laboratory technician performed a series of 10 fold serial  dilutions shown below. he plated 0.1 mL from each dilution tube onto NA and got the follow numbers per plate dilution 1:10 1:10 1:100 1:1000 1:10000 1:100000 colony count >1000 >1000 808 303 38 3 calculate the concentration of bacteria in the undiluted stock (in CFU/mL)

Five ml of bacterial culture is added to 45 ml of sterile diluent. From this suspension, the following serial dilutions were made, two 1:100 and one 1:10 dilutions, and 0.1 ml is plated onto Plate Count Agar from the last dilution. After incubation, 186 colonies were counted on the plate. 1. What is the dilution factor, or how much of the original sample was diluted?

What will pose an ethical issue in these procedures are performed - sterilization?

Subculture and Colony Morphology Descriptions Following identification of the Gram-negative isolate and Gram-positive isolate, you next subculture each onto fresh nutrient agar plates.  Briefly describe the subculture process in three or so sentences and what this allowed you to achieve; follow this with colony morphology descriptions of each.    Description:           Isolate A – Describe:    Colony morphology:    Medium & incubation temperature: Isolate B – Describe:    Colony morphology:    Medium & incubation temperature:

Which isolation technique is best used in isolating microorganisms (in countable good plates) from a gram of soil sample with expectedly high microbial count?  A. Streak Plate technique B. Serial Dilution-Pour Plate technique C. Spread Plate technique D. Hanging Drop technique 2. Which materials are needed in isolating bacteria using Streak Plate technique? Check all that apply.  ( )nutrient agar plate ( ) inoculating loop ( ) microbial inoculum ( ) flame source 3. Which term refers to that solution of sterile distilled water/normal saline/peptone water used to "thin out" dense microbial populations in Serial Dilution-Pour Plate technique used in the isolation of microorganisms?  A. inoculum B. culture medium C. diluent D. microbial culture

Which of the following tests will help me differentiate between an unknown bacteria that is either Salmonella typhimurium and Serratia marcescens Wet Mount (motility testing) Endospore Staining Acid Fast Staining Differential & Selective Media (MacConkey, PEA, EMB, MSA Agar, Blood Agar, etc.) Oxidative-Fermentative Test Carbohydrate Fermentation MR-VP Testing Catalase Test

Hello, Please answer the following attached Microbiology question AND ANSWER ALL 3 PARTS COMPLETELY. Thank you. *If you actually solve all of the THREE PARTS (QUESTIONS) CORRECTLY AND COMPLETELY, I will 100% leave a thumbs up. Microbiology Question: "The attached picture is a gram stain for mycobacterium tuberculosis. What does the Gram Stain photo look like? Based on this attached picture, please explain whether it is Gram-positive or negative. Also, please explain the colors chemistry and shape. Thank you

List the steps of the gram staining procedure in proper sequence and indicate the color of gram-positive and gram-negative bacteria after each step.

What Gram-negative bacterium might you come into contact with in a unsanitary hot tub?    asap please  detail explanation needed

Topic: Spread-Plate Method  Agar was not completely set prior to inoculating with the organism. Effect:Rationale:

Why is it best to use sterile distilled water in the preparation of microbial suspension and dry smears for slide preparation? What possible error could happen if a glass slide is reused for slide preparation?

A class of 15 students (8 males and 7 females) will need to culture an unknown bacteria for a specific activity where 5 nutrient agar pates per female student and 3 agar slants per males student are needed to prepare. agarplate: 25mL Agar slant: 10mL Broth tube: 8mL Nutrient Agar: Yeast extract: 2g/L peptone: 5g/L Sodium chloride: 5g/L Agar powder: 15g/L

Complete the following questions for your gram positive coccus unknown organism  (a) What test did you run for your second test on your gram positive coccus organism? MSA Test  (b) What was the result of this second test? Positive  (c) What does the result of your second test tell you about the biological and/or metabolic characteristics of your gram positive coccus unknown microorganism?   Please answer  (d) If your organism requires a third test, what did you do for your third test on your gram positive coccus unknown organism and what was the result of this test? If it does not require a third test, just put "Gram positive coccus identified". Please answer

If SIM medium was used for motility determination for Proteus vulgaris, what noticeable change to the medium was observed?

Out of twelve tests that can be performed:  Gram Stain Wet Mount Endospore Staining Acid Fast Staining Differential & Selective Media (MacConkey, PEA, EMB, MSA Agar, Blood Agar, etc.) Oxidative-Fermentative Test Carbohydrate Fermentation MR-VP Testing Indole Production Citrate Utilization Triple Sugar Iron Testing Catalase Test.  Which four tests are the best fit to help identify bacteria that is unknown? Possible bacterias that are being observed are:    Enterobacter aerogenes Escherichia coli Micrococcus luteus Proteus vulgaris Pseudomonas aeruginosa Salmonella typhimurium Serratia marcescens Staphylococcus aureus Staphylococcus epidermidis

Solve the identity of an unknown bacterial specimen by creating a dichotomous key.   Categories: Gram stain, Mannitol salt agar,MacConkey agar, Catalase, Oxidase, Casein hydrolysis, Nitrate reduction, Citrate test, Urease test, Sim Medium Streptoccocus ID: 1) Bile Esculin Test 2) Bacitracin Test  3) Blood Agar Plate NaCl Broth Staphylococcus ID: 1) Mannitol Salt Agar 2) DNA Hydrolysis 3) Coagulase Test 4) Novobiocin Test    Possible Organisms Alcaligenes faecalis Enterobacter aerogenes Enterococcus faecalis Escherichia coli Proteus vulgaris Pseudomonas aeruginosa Salmonella arizoniae Staphylococcus aureus Staphylococcus epidermidis Staphylococcus saprophyticus Streptococcusbovis Streptococcus pyogenes

John performed a side-by-side Gram satin of a known Gram positive and known Gram negative organism. Unfortunately, he forgot to do iodine step. When he observed his completed slide under oil immersion, what do you think he saw?

a food sample with an unknown number of contaminating bacteria was serial diluted to 10-6. the 10-6 plate contained 96 colonies. What was the original microbial concentration? Show your work.

You are testing unpasteurized milk for the presence of bacterial contamination. Starting from the undiluted milk, you do serial dilutions, and plate 0.5 ml of 4th dilution on agar. If you counted 78 CFUs from the 4th plate, how many bacteria/ml do you expect? (show solution) Do you think standard plate counts are very accurate? Why or why not?

What part of the tube changes color first (in Resazurin Reduction Test between Pasteurized and Raw Milk)?

What physical appearance (Solid, liquid, semi-solid) of following Media: Broth tube, agar slant tube, agar deep tube, and agar plate. What exactly am I testing when I Introduce an inoculum with a needle on an agar deep tube?

Disinfectants and Sterilization Procedures Complete the table by putting (+) for growth of microorganisms or (–) absence of growth of microorganisms. Disinfectant Concentration Growth after time of exposure (minutes) Control 5 minutes 10 minutes 15 minutes Sodium hypochlorite 5%         Sodium hypochlorite 0.05%         Alcohol 70%         Alcohol 40%         Iodophor (Betadine) 10% solution         Mouthwash Cetylpyridinium Chloride - 0.075% Sodium Fluoride - 0.05%

A plate has 72 colonies with a total dilution factor of 10-7, 0.1 ml was pipetted onto the plate, what was the original CFU/ml concentration of that sample?

If there is 50 bacterial colonies on a 1:1000 dilution streak plate. How many cfu/mL are there?

The student advises using the same selection procedures and inoculating a 5 mL overnight culture with the transformed cells instead of searching for transformed coli on LB agar plates in order to save time. Why isn't this a wise decision?

You were given a mixed nutrient agar broth culture of bacteria  1a. How will you determine the different types of bacteria present in the mixed culture without using an agar plate 1b. How will you make a pure culture of these bacteria on a slant nutrient agar 1c. How will you identify these bacteria from the pure culture without using an agar plate

When you interpret a Gram-stained smear, you should also describe the morphology (shape) of the cells, and their arrangement. In the figure below, there are two distinct types of bacteria, distinguishable by Gram stain reaction, and also by their shape and arrangement. Below, describe these characteristics for both bacteria:     Gram positive bacterium Gram negative bacterium Morphology cocci bacillus Arrangement

in the document you submit, please describe the results for this test… (like yellow equals what?) Methyl Red and Voges-Proskauer (MRVP) Test: 1) Give me the expected results for Enterobacter aerogenes and Escherichia coli (for each bacteria, give me the MR result and VP result)

To dilute a bacterial culture, 500 μl of a 16 hour culture is mixed with fresh culture media to a final volume of 5 ml. How did you calculate it?. Single line text.