unsure if this is corect, please help 013: 1pt. Practice-niew scenario: You have

Question

unsure if this is corect, please help

013: 1pt. Practice-niew scenario: You have 10g of yogurt it is equally distributed. What dilution do you have right.now and dilute it in 990 ml of water-you blend it until os otal dieton s oake Iml of the sample from the previous question and add it to 99ml of water. What is your 101 lo/ QiS: Ipt. You use 0.1ml of the diluted sample from the previous question Your final total dilution is: count the number of colonies that grew on this plate and you have 97. What was the CFU/ml of the bacieria that were in your original sample? Make sure it s n scientife notation. it is in scientific notation. 8: 1pt. You now want to know the total number of CFU or microbes that were in the food sample in the first place. How do you figure this out? Show your math. 4

Explanation / Answer

As In question no 13 suggest that 10g yoghurt is mixed with the 990 ml of water. Here yoghurt in gram but it having some volume also and we consider that 10g eual to 10 ml.

Here final volume is =990+10= 1000 ml

10 / 1000= 1/100 or 1: 100 or 10-2or 0.01

Here you write correctly but when you make the superscript then did the mistake.

Similarly in question 14,

Final volume is 1+99=100

1/100

But you have taken a 10-2

1* 10-2 / 100 = 1/ 100* 100 or 1/10000 or   10-4

Similarly in next question

1* 0.1/10000=    10-5 dilution

For question no 17 you must know the fomula of CFU/ml

CFU/ml= No of colonies * dilution/ amount of the volume plated

= (97 * 10000)/0.1= 97 * 105 cells/ml or 9.7 * 106

  

As the initial sample is 10 ml hence

10 * 9.7 * 106 =9.7 * 107

  

You did the correct calculations but first calculation was wrong hence all the below dependent questions are wrong.

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.