1. Bacteria
and
Food
Safety
The
objective
of
this
research
is
to
compare
bacteria
inactivation
action
between
microwave
and
traditional
external
heating
methods.
Additional
comparisons
examine
the
effect
of
water
activity
on
bacterial
inactivation
of
both
raw
and
cooked
chicken.
Chicken
was
cooked
on
a
skillet
for
low
water
activity
traditional
samples
(LWAT),
boiled
in
a
pot
of
water
for
high
water
activity
traditional
samples
(HWAT),
microwaved
on
a
plate
for
low
water
activity
microwave
samples
(LWAM),
and
microwaved
in
a
bowl
of
water
for
high
water
activity
microwave
samples
(HWAM).
Each
variation
was
sampled
during
the
initial
cooking
and
during
re-­‐heat
using
the
same
heating
method
following
proper
HACCP
cooling
procedure.
Bacterial
inactivation
of
samples
was
determined
by
rubbing
surface
of
chicken
at
designated
time
then
streaking
to
tryptic
soy
agar
(TSA)
plates
using
a
single-­‐use
sterile
cotton
swab.
Swabs
were
taken
at
baseline,
averaged
total
cooking
time
to
165F,
1/3
total
cooking
time,
and
2/3
total
cooking
time.
Plates
were
incubated
at
36C
for
48
hours.
Resulting
bacterial
growth
was
categorized
based
on
aggressiveness
and
coherency.
Results
show
significant
bacterial
growth
at
baseline
of
both
initial
heat
and
re-­‐heat
samples.
Initial
heat
showed
complete
inactivation
of
bacteria
at
1/3
total
time
and
beyond
for
HWAT,
HWAM,
and
LWAM
samples.
Bacteria
persisted
during
1/3
and
2/3
cook
times
of
LWAT
samples.
Bacteria
were
completely
inactivated
at
total
cooking
time
in
LWAT
samples.
Re-­‐heat
samples
showed
the
exact
same
trend.
As
expected,
LWAT
samples
exhibited
bacterial
growth
long
after
other
conditions.
Microwaves
quickly
killed
bacteria
similarly
to
HWAT
method.
Surprisingly,
HWAT
performed
as
well
as
microwaves.
Any
heating
method
that
achieves
appropriate
internal
temperature
should
yield
safe
food.
Microwaves
and
high
water
activity
traditional
heat
are
more
efficient
heating
methods
that
are
also
highly
effective
at
inactivating
bacteria.