changes did not appear to drastically reduce pathogen populations;
however reductions were statistically significant (p < 0.05). RH
measurements taken during dehydration ranged from 8.2 to 51.5%
on the low and high ends. HPP treatments of two cycles of 550 MPa
for 60 s, were performed immediately following vacuum packaging
of the dehydrated jerky, resulting in variable reductions in pathogen
populations. The 2-cycle HPP treatment was found to have the
greatest effect on Salmonella spp. populations with reductions of
3.2 log10 CFU/strip. It is important to note that reductions on individual
samples were variable. Small reductions of
L. monocytogenes (1.2 log10 CFU/strip) and S. aureus (1.3 log10 CFU/
strip) populations also were observed following HPP treatments;
however, E. coli O157:H7 populations did not significantly change as
an immediate result of HPP. Fourteen day storage (20e22 C) of
HPP-processed samples resulted in further reductions in Salmonella
spp. (1.4 log10 CFU/strip), and E. coli O157:H7 (1 log10 CFU/strip)
populations. Populations of L. monocytogenes and S. aureus
increased slightly following 14 day vacuum packaged storage;
however these increases were likely due to higher variation among
jerky samples. Interestingly, total log reductions of >5 log CFU/strip
were observed in Salmonella spp. over the course of the experiment,
with E. coli O157:H7 reductions reaching 4.4 log10 CFU/strip
after 14 days of vacuum packaged storage.