High Pressure Destruction Kinetics of Clostridium Sporogenes Spores in Salmon Slurry at Elevated Temperatures

Figures & data

Figure 1 Schematic diagram of the high pressure experimental setup showing the insulator details.

Table 1 Experimental setup and temperature control for the kinetic tests

System pressure (MPa)	Target process temperature (°C)	Required initial temperature (°C)	Mean process temperature achieved (°C)	Standard deviation in process temperature (°C)
	80	52.4	79.57	0.51
700	90	61.0	88.31	1.48
	100	69.5	99.88	0.30
	80	49.8	80.31	0.47
800	90	58.3	87.65	2.46
	100	66.7	100.1	0.30
	80	47.4	80.94	0.65
900	90	55.8	89.67	1.12
	100	64.2	99.97	0.28

Table 2 Decimal reduction time of C. sporogenes 7955 spores in salmon slurry subjected to thermal treatment

Pressure (MPa)	Temperature (°C)	D value (min)	R^2	Z value (°C)
0.1	90	104.2	0.99
	95	19.9	0.99	8.8
	100	7.5	0.98	R^2 = 0.98

Figure 2 Schematic for temperature compensation of kinetic parameters.

Figure 3 Survivors curves for C. sporogenes 7955 spores in thermally treated salmon meat slurry (1 atm) at selected temperatures: (▲) 80°C, (■) 90°C, (●) 95°C, (♦) 100°C.

Figure 4 Sample temperature in the insulated chamber and pressure chamber medium temperature during a pressure treatment at 700 MPa, 80°C for 24 min.

Figure 5 Uncorrected (a) and temperature corrected (b) survivors of C. sporogenes 11437 spores in salmon meat slurry pressure treated at 700 MPa and different temperatures: (♦) 80°C, (■)90°C, (▲) 100°C.

Figure 6 Uncorrected (a) and temperature corrected (b) survivors of C. sporogenes 11437 spores in salmon meat slurry pressure treated at 800 MPa and different temperatures: (♦) 80°C, (■)90°C, (▲) 100°C.

Figure 7 Uncorrected (a) and temperature corrected (b) survivors of C. sporogenes 11437 spores in salmon meat slurry pressure treated at 900 MPa and different temperatures: (♦) 80°C, (■)90°C, (▲) 100°C.

Table 3 Effect of pressurization come-up time (CUT) and depressurization come-down time (CDT) on C. sporogenes 7955 spores reduction

	Spores reductions Log (N/No*10^6)
Process temperature (°C)	Pressure 700 (MPa)	Pressure 800 (MPa)	Pressure 900 (MPa)
80	−0.07 ± 0.03	0.01 ± 0.07	0.01 ± 0.06
90	0.01 ± 0.03	0.16 ± 0.03	0.24 ± 0.03
100	0.67 ± 0.06	0.80 ± 0.04	1.35 ± 0.16

Table 4 Decimal reduction time (D values) of C. sporogenes 7955 spores in salmon meat slurry with HP and thermal treatment

		Uncorrected		Corrected
Pressure (MPa)	Temperature (°C)	D value (min)	R^2	D value (min)	R^2
700	80	32.8	0.97	31.2	0.99
	90	9.0	0.90	6.8	0.99
	100	1.3	0.95	1.3	0.99
800	80	13.6	0.94	14.0	0.97
	90	5.0	0.96	4.0	0.98
	100	1.0	0.96	1.0	0.97
900	80	9.4	0.98	10.9	0.98
	90	2.8	0.92	2.9	0.99
	100	0.6	0.99	0.6	0.99

Table 5 High pressure Z_P value of C. sporogenes 7955 spores in salmon meat slurry subjected to HP and thermal treatments

	Uncorrected		Corrected
Pressure (MPa)	Zp value	R^2	Zp value	R^2
700	14.4	0.98	14.5	0.98
800	17.5	0.90	17.3	0.86
900	16.4	0.93	15.5	0.94

Figure 8 Uncorrected (a) and corrected (b) D value curves of C. sporogenes 11437 spores in salmon meat slurry subjected to HP and thermal treatments at different temperatures: (♦) 80°C, (■)90°C, (▲) 100°C as a function of pressure.

Table 6 High pressure Z_T value of C. sporogenes 7955 spores in salmon meat slurry subjected to HP and thermal treatments

	Uncorrected		Corrected
Temperature (°C)	ZT value	R^2	ZT value	R^2
80	370	0.95	440	0.92
90	395	0.99	535	0.98
100	535	0.98	550	0.96

Figure 9 Uncorrected (a) and corrected (b) D value curves of C. sporogenes 11437 spores in HP treated and thermally treated salmon meat slurry at different pressures: (♦) 700 MPa, (■) 800 MPa, (▲) 900 MPa, (▲) 0.1 MPa as a function of temperature.

Table 7 Predicted decimal reduction time (D values) of C. sporogenes 7955 spore in HP and thermal treated salmon meat slurry at higher temperatures

	Extrapolated
	D value (min) at Temperature(°C)
Pressure (MPa)	105	110	115	120	121
700	0.60	0.27	0.12	0.056	0.048
800	0.52	0.27	0.14	0.071	0.062
900	0.28	0.13	0.064	0.031	0.026
0.1	1.8	0.48	0.13	0.035	0.027