40 Ms Pickles weighed 45 grams of ground turkey and mixed it

40 Ms. Pickles weighed 45 grams of ground turkey and mixed it in 155 ml of water. Alter fitration-thru a cheese cloth, she measured only 175 ml of ground turkey solution and she plated 200ul on duplicate EMB plates from a 10-4 dilution from the filtrate. On incubation she counted an average of 80 colonies on the EMB plates. You must show all calculations to get full points. (16 points) a. What is the concentration per ml of ground turkey in the original mix? b. What is the concentration (CFUlml of coliform bacteria in the 175 ml sample? c. What is the total number of bacteria in the 175 ml sample? d. How many bacteria per gram of ground turkey solution.

Solution

45 grams of ground turkey was mixed with 155 ml of water. Total volume (TV) is then 45+155=200ml assuming specific gravity of ground turkey is equal to water. After filtration through a cheese cloth she recovered 175 ml of turkey solution so 200-175=25 gm not dissolved. 200 micro litre was plated EMB plates from a 10 to the power minus 4 dilution of the filtrate means 10000 times diluted actually 200/10000=0.02 micro litre was used to plate each of the two plates.

Avarage 80 colonies are found in 2 plates i.e. 80*2=160 colonies were originally formed out of 0.02*2 micro litre

a. Concentration of ground turkey in original mix of 200 ml is

45gm/200ml=0.225gm/ml

b. CFU/mL (colony-forming units per milliliter) of coloform bacteria in the 175 ml sample is calculated as

cfu/ml = (no. of colonies x dilution factor) / volume of culture plate
=(80*1/10000)/(175)
=1.4/ml

c. 200/10000=0.02 micro litre plated volume contained 80 colonies in avarage i.e.: 0.00002 ml contained 80 bacteria
175 ml would have contained 80*(175/0.00002)=70,00,00,000

d. to calculate bacteria per gram of ground turkeey solution 200ml will be taken into calculation so 80*(200/0.00002)=80,00,00,000