Correll Lab1
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Transcript of Correll Lab1
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Results:
PART 1
T=105C T=110C T=115C T=120C
t
(min) survivors log(surv)
t
(min) survivors log(surv)
t
(min) survivors log(surv)
t
(min) survivors log(surv)
60 9.10E+08 8.96E+00 20 1.20E+09 9.08E+00 3 1.30E+09 9.11E+00 1.33 1.10E+09 9.041393
90 6.80E+08 8.83E+00 30 8.80E+08 8.94E+00 5 9.20E+08 8.96E+00 1.67 7.10E+08 8.851258
120 4.00E+08 8.60E+00 40 4.80E+08 8.68E+00 10 3.30E+08 8.52E+00 2 7.20E+08 8.857332
150 2.80E+08 8.45E+00 60 2.80E+08 8.45E+00 15 1.10E+08 8.04E+00 4 7.60E+07 7.880814
180 2.50E+08 8.40E+00 90 7.00E+07 7.85E+00 20 2.70E+07 7.43E+00 6 7.70E+06 6.886491
300 6.40E+07 7.81E+00 120 8.70E+06 6.94E+00 30 8.40E+05 5.92E+00 8 3.50E+05 5.544068
390 8.20E+06 6.91E+00 180 1.80E+04 4.26E+00 45 1.70E+03 3.23E+00 10 3.62E+03 3.558709
480 1.32E+06 6.12E+00 60 2.00E+01 1.30E+00 12 2.60E+02 2.414973
Table 1 Data of surviving population at time of withdrawal
Graphs 1 through 4 show the calculated decimal reduction times and the first order reaction
rate constant for temperatures 105C, 110C, 115C and 120C.
Graph 1 Survivor Curve Showing Logarithmic Order of Death at 105C
y = -0.0065x + 9.4559
0.00E+00
1.00E+00
2.00E+00
3.00E+00
4.00E+00
5.00E+00
6.00E+00
7.00E+00
8.00E+00
9.00E+00
1.00E+01
0 100 200 300 400 500 600
Survivors
Time (min)
Survivor Curve Showing Logarithmic Order of
Death at 105C
D= 147.97 minK=slope=-0.0065
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Graph 2 Survivor Curve Showing Logarithmic Order of Death at 110C
y = -0.029x + 9.9758
0.00E+00
1.00E+00
2.00E+00
3.00E+00
4.00E+00
5.00E+00
6.00E+00
7.00E+00
8.00E+00
9.00E+00
1.00E+01
0 20 40 60 80 100 120 140 160 180 200
Survivo
rs
Time (min)
Survivor Curve Showing Logarithmic Order ofDeath at 110C
D= 33.17min
K=slope=-0.029
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Graph 3 Survivor Curve Showing Logarithmic Order of Death at 115C
y = -0.1419x + 9.8994
0.00E+00
1.00E+00
2.00E+00
3.00E+00
4.00E+00
5.00E+00
6.00E+00
7.00E+00
8.00E+00
9.00E+00
1.00E+01
0 10 20 30 40 50 60 70
Survivors
Time (min)
Survivor Curve Showing Logarithmic Order of
Death at 115C
D= 7.77 min
K=slope=-0.1419
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Graph 4 Survivor Curve Showing Logarithmic Order of Death at 120C
PART 2
a) Temperature Dependency Factor (Z-value):Temp C D value log(Dval)
105 1.55E+02 2.190332
110 5.10E+01 1.70757
115 7.00E+00 0.845098
120 2.60E+00 0.414973Table 2 Temperature and D value Table
y = -0.6241x + 10.14
0
1
2
3
4
5
6
7
8
9
10
0 2 4 6 8 10 12 14
Survivors
Time (min)
Survivor Curve Showing Logarithmic Order of
Death at 120C
D= 1.61 min
K=slope=-0.6241
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Graph 5 Thermal Death Time Curve
b) Arrhenius Energy (Ea):Temp C Temp Kel 1/T Kel -k min ln(k)
105 3.78E+02 2.65E-03 0.0065
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5.03595
110 3.83E+02 2.61E-03 0.029
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3.54046
115 3.88E+02 2.58E-03 0.1419
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1.95263
120 3.93E+02 2.54E-03 0.6241
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0.47144
Table 3 Reciprocal of absolute temperature and reaction rates in natural log cycles.
y = -0.1238x + 15.214
0
0.5
1
1.5
2
2.5
104 106 108 110 112 114 116 118 120 122
log(Dvalue)(minutes)
Temperature ( C )
Thermal Death Time Curve
Z= 8.0 C
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Graph 6 Arrhenious Plot
PART 3
a) Initial concentration=100 per containerLevel of acceptable spoilage= 1/100000=1E-5
SV=7
PART 4
a) D120 C.botulinum = 0.20 minutes
y = -45399x + 115.04
-6
-5
-4
-3
-2
-1
0
2.52E-03 2.54E-03 2.56E-03 2.58E-03 2.60E-03 2.62E-03 2.64E-03 2.66E-03
ln(k)
1/T (Kel^-1)
Arrhenious Plot
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b) D120 Enzyme = 0.5 minutes with 99% Enzyme reduction needed.
PART 5
a) Process temperature at 113C
b) Process temperature at 135C
PART 6
a) Sterilizing Value (log cycle reduction) at 135C for 1 full minute
Discussion:
In Part 1 of the experiment, the Decimal Reduction Time (D) and the first order reaction rate constant
(K) were calculated graphing the logarithmic order of death of the population through time at eachspecific temperature. By looking at the graph, the time required to get one log cycle in population was
approximated and D was obtained. Also, a more accurate way of finding D is to using the equation
. Moreover, the first order reaction rate constant or K value was calculated by getting
the slope of the best fitted line. Results of these values show that the fastest temperature to complete a
cycle was at the highest temperature of 120C, taking 1.61 minutes. The slowest was 147.97 minutes at
105C.
In Part 2, the temperature dependency factor (Z) was obtained by graphing the Thermal Death Time
Curve and calculating the temperature required for a log cycle to complete. In this case, by looking at
the graph we got 8C. Furthermore, the Arrhenious activation energy was calculated by graphing anArrhenious plot and getting the slope of the best fitted line. This value helped us find the activation
energy (Ea) by multiplying the gas constant times the slope. The Ea was found to be 377.45 kJ/mol.
Part 3 was done by applying the equation of the best fitted line found in the Thermal Death Time Curve
to obtain a D value at 121.1C. Then, the equation was used to get the common
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lethality value. The common lethality curve is essential for food conservation and for the control of
spoilage of food.
For Part 4, the equation was used to calculate the cooking time to provide a safe botch cook
as well as an adequate blanch process under the given conditions. For C.botulism it took 2.4 minutes to
cook safely and for the enzyme, it took 1 minute.
In Part 5 of this experiment, the line equation found in the Thermal Death Time Curve graph was used to
calculate the D value at the different process temperatures. Then, by using a sterility value of 7 log
cycles the critical process hold time was found at 113C and 135C.
Lastly, the sterilizing value in Part 6 was found using the equation,
, for a process of 1 full
minute. Book problems are attached in the appendix section of this lab report.