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Title of Research:
Evaluation of High Humidity and Wet Marinade
Methods for Pasteurization of Jerky |
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Place:
Utah State University, Logan, UT
Authors:
Drs. K. Allen, D. Cornforth, D. Whittier, M.
Vasavada, and B. Nummer
Purpose:
To evaluate the effects of high humidity (>90%) or
wet marinade pasteurization on beef jerky’s
characteristics (water activity [Aw], moisture/protein
ratio, total aerobic plate count [TAC]) and sensory
properties.
Summary:
The USDA Food Safety and Inspection Service in
March 2004 issued a compliance guideline for
beef jerky processors, requiring manufacturers
who use time–temperature guidelines for
pathogen destruction to take into account the
humidity of the oven, especially in
high-altitude areas of the country where
relative humidity is low. This study compared
traditional oven-drying practices to high
humidity or wet marinade methods for the water
activity, moisture/protein ratio, microbial
load and the sensory properties (flavor,
texture, appearance).
The study followed the USDA guidelines when
conducting four test methods: one oven heating
method and three marinade-heating methods. This
study demonstrated jerky pasteurized by the
nonmarinade method A (oven heating method -
76.6 ºC dry bulb, 54.4 ºC oven wet bulb
temperature for 1 hour) had generally lower
TACs than jerky from the three marinade
pasteurization methods and the highest sensory
scores for spice intensity and interior cured
color (redness).
Jerky pasteurized before oven drying by method
B (long time/low temperature - 54 ºC for 121
minutes in marinade) had higher TACs than other
methods. Method C (intermediate
time/temperature - 60 º C for 12 minutes in
marinade) and method D (short time/high
temperature - 70º C for 1 second in marinade)
had approximately 2-log reduction in TAC but
the jerky was less spicy and somewhat darker
than jerky from method A. Extruded jerky
(1.5-cm thickness) was similar to intact jerky
for spice flavor intensity and interior
redness, but required longer drying time to
reach the target Aw of 0.85. In addition, the
long time/low temperature combinations listed
in Appendix A of the USDA time–temperature
tables for heat inactivation of pathogens may
not adequately control spoilage organisms.
Based on this study, it is recommended that
processors confirm the efficacy of long
time/low temperature marinade heating processes
with their own products.
Benefits:
Jerky pasteurized before oven drying by method
B (long time/low temperature - 54 ºC for 121
minutes in marinade) had higher TACs than other
methods. Method C (intermediate
time/temperature - 60 º C for 12 minutes in
marinade) and method D (short time/high
temperature - 70º C for 1 second in marinade)
had approximately 2-log reduction in TAC but
the jerky was less spicy and somewhat darker
than jerky from method A. Extruded jerky
(1.5-cm thickness) was similar to intact jerky
for spice flavor intensity and interior
redness, but required longer drying time to
reach the target Aw of 0.85. In addition, the
long time/low temperature combinations listed
in Appendix A of the USDA time–temperature
tables for heat inactivation of pathogens may
not adequately control spoilage organisms.
Based on this study, it is recommended that
processors confirm the efficacy of long
time/low temperature marinade heating processes
with their own products.
The full report on this research can be found
on the Fiscal Year 2005 table under the column
Food Safety Technologies - Additional
Information.
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