mikpang 6.1. pengendalian mikroba perlakuan sanitasi
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8/12/2019 MIKPANG 6.1. Pengendalian Mikroba Perlakuan Sanitasi
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1
Department of Food Science and Technology
Bogor Agricultural University
MICROBIAL CONTROL:
CONTROL BY SANITATION
CONTROL BY HIGH TEMPERATURE
CONTROL BY LOW TEMPERATURE
Winiati P. Rahayu
Department of Food Science and Technology
Bogor Agricultural University
Mechanism of Antimicrobial Action :
Denature proteins/ produce stress protein
Sublethally injured. Injury in :
Cell wall
DNA
Ribosomal RNA
Enzymes Dead damaged in some functional and
structural component
Bacterial spores : lose spore coat, Inability to germinate
Inability to outgrow Methods
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g
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Department of Food Science and Technology
Bogor Agricultural University
Basics Steps of a Cleaning Procedure:
Pick up debris, Prerinse and wet, Wash with
cleaning agent, Rinse, Inspect, Sanitize,
Prevent recontamination.
Sanitizing: Heat, iradiation, chemicals
Chemicals are used most often in foodprocessing
facilities :
Chlorine, iodophor, quats, acid
Chlorine :Works on a broad range of microorganism,cheap, no rinsing required at 200 ppm or less, available
as liquid or granules, not affected by hard water
Department of Food Science and Technology
Bogor Agricultural University
Ideal Sanitizer :
Destroys all types of vegetatives bacteria, yeasts, and molds
quickly
Works well in different environments (i.e., soiled surfaces, hard
water, different pHs, soap or detergent residues)
Does not irritate skin, nontoxic
Cleans well
Dissolves in waterStable as purchased (concentrate) and as used (diluted)
Easy to use
Readily available
Inexpensive
Easy to measure
No offensive odor
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Department of Food Science and Technology
Bogor Agricultural University
Control By High Temperature
The pasteurization :
63/72 oC for 30 min/15 second (LTLT/HTST)
& Ultra, exp: 140oC for 0.01 second
Canned foods are sometimes called commercially sterile to
indicate that no viable organisms can be detected by usual
cultural methods or the number of survivors is so low as to be
of no significance under the conditions of canning and storage
www.hyewonp
ack.c
om
mis.dost.gov.p
h
Department of Food Science and Technology
Bogor Agricultural University
Water In the presence/increases of water (humidity, moisture,
water activity), the heat resistance of microbial cells
decrease
Water allows for thermal breaking of peptide bonds.
Fat In the presence of fats, the heat resistance of some m.o.
increases.
The heat protective effect of long-chain fatty acid of
Clostridium botulinum the long-chain fatty acid are
better protectors than short-chain acids.
Factor Affecting of Heat Resistant
Salts Some salts may decrease aw, and thereby increases
heat resistancewww.t
hereefshop.com.au
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Department of Food Science and Technology
Bogor Agricultural University
Proteins and other substances
During heating, protein have a protective effect on m.o.
pH M.o. are most resistant to heat at their optimum pH of
growth (generally about 7.0)
When pH is lowered or raised from the optimum value
increase in heat sensitivity
Carbohydrates Sugars causes an increase of heat resistance in
m.o.
The effect is at least in part due to the decrease in
aw.caused by high concentrations of sugars.uchovani.jidla.navajo.cz
www.chemistryland.com
Department of Food Science and Technology
Bogor Agricultural University
Number of m.o.
The larger the number of m.o., the higher is the degree of heat
resistance
The mechanism of heat protection by large microbial populations
is due to the production of protective substance excreted by the
cells
Age of m.o.
Most resistant to heat while in the stationary phase of growth
(old cells) and less resistant during the logarithmic phase
Growth temperature
The heat resistance of m.o. tends to increase as the temperature
of incubation increase
A decrease in heat resistance : presence of heat-resistant
antibiotics, SO2, and other microbial inhibitors
Inhibitory compound
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Department of Food Science and Technology
Bogor Agricultural University
Time and temperature
The longer the time of heating, the greater the
killing effect of heat
As temperature increases, time necessary to
achieve the same effect decreases
Effect of ultrasonics
The exposure of bacterial endospores to ultrasonic
treatments just before or during heating result in a
lower heat resistance of spores
www.t
hetipsbank.com
Department of Food Science and Technology
Bogor Agricultural University
Psychrophilic m.o. are the most heat sensitive, followed by
mesophiles and thermophilies
Sporeforming bacteria are more heat resistant that non-sporeformers
Thermophilic sporeformers are more heat resistant than mesophilic
sporeformers
Gram + bacteria tend to be more heat resistant than Gram -
Yeasts and molds tend to be fairly sensitive to heat
Heat Resistant of M.O
Yeasts ascospores are only slightly
more resistant than vegetative
yeasts
The asexual spores of molds tend to
be slightly more heat resistant than
mold mycelia www-zis-chwww.alken-murray.com
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Department of Food Science and Technology
Bogor Agricultural University
Thermal death time
Thermal death time (TDT) is the time necessary to kill agiven number of organisms at a specified temperature
Dvalue
D value is decimal reduction time or the
time required to destroy 90% of the m.o.
This value is equal to the reciprocal of the slove ofthe survivor curve an is a measure of the death rate
of an organism
Thermal Destruction of M.O
www.hyewonpack.com
Department of Food Science and Technology
Bogor Agricultural University
5 10 15 20 25 30
10
100
1000
570
340
65
19
4.5
1.3
D240=8
(1.250)
01
Survivors(logscale)
Time of heating (min)
Rate of destruction
curve. Spores of
strain F.S. 7 heated at
240
o
F in canned peabrine pH 6.2.
Thermal death time curve
F value This value is the equivalent time, in minute, at
250oF of all heat considered
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Department of Food Science and Technology
Bogor Agricultural University
zvalue
D
values,minutes(logscale)
oF220 230 240 250 260
10
100113
31
8
2.3
0.65
=17.5
0
1
mis.dost.gov.ph
www.retort.com.tw.jpg
Department of Food Science and Technology
Bogor Agricultural University
12- D concept
The 12-D concept refers to the process lethality
requirement in the canning industry and implies that the
minimum heat process should reduce the probability of
survival of the most resistant C, botulinumsporesIf D = 3 minutes
12 D = 36 minutes
This concept is observed only for foodsabove pH 4,6
If it is assumed that each container of food
contain only one spore of C. botulinum, F0
may be calculated by use of the general
survivor curve equationwww.jamesfood.com
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Department of Food Science and Technology
Bogor Agricultural University
Examples
Z = 17.5
140oF in 3.5 minutes
157.5oF in 0.35 minutes
122.5oF in 35 minutes
F0 = Dr(log alog b)
F0
= 0.21 (log 1log 1012)
F0 = 0.21 X 12 = 2.52
For high acid = 5 D
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Department of Food Science and Technology
Bogor Agricultural University
Control by Low Temperature
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Department of Food Science and Technology
Bogor Agricultural University
Foodborne m.o. grow slowly at temperature above
freezing and generally stop at subfreezing temperatures
The rate of enzyme catalyzed is dependent ontemperature
The temperature coefficient (Q10) may be generally
defined as follows :
(Velocity at a given temp. + 10oC)
Velocity at T
Q10 =
The Q10for most biological system is 1.5-2.5Temperature is effect to RH, pH, other parameters of
microbial growth
Department of Food Science and Technology
Bogor Agricultural University
There are three distinct temperature ranges for low-
temperature stored foods
1. Chilling : between refrigerator (5-7oC) and
ambient 10-15oC temperature
2. Refrigerator temperatures : between 0-7oC
3. Freezer temperatures : at or below18oC
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Department of Food Science and Technology
Bogor Agricultural University
Bacterial species and strains can grow at or below
7oC, Growth at temperatures < 0oC is more likely for
yeasts and molds than bacteria.
Bacteria have been reported to grow at20oC and
around12oC.
The lowest recorded temperature of growth for m.o. of
concern in food is34oC (pink yeast).
Foods that are likely to support microbial growth at
subzero temperatures include fruit juice concentrates,
bacon, ice cream, and certain fruits. These products
contain cryoprotectants that depress the freezing point
of water.
Need blancing before freezingwww-global_b2b_network-
com
www.denniskunkel.com
Department of Food Science and Technology
Bogor Agricultural University
Effect of Freezing on Microorganisms
There is a sudden mortality immediately on freezing,
varying with species
The proportion of cells surviving after freezing die
gradually when stored in the frozen state
This decline in numbers is relatively rapid at
temperatures just below the freezing point, especially
about2oC, but less so at lower temperatures, and it is
usually slow below20oC
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Department of Food Science and Technology
Bogor Agricultural University
At temperatures -2oC, water different types of
bacteria, molds, and yeasts can grow in a foodbut the lag and exponential phases become longer
Cells of some mesophiles and thermophiles can :
Sublethally injured
Die if the temperature drops below 4.5oC
The rate of freezing and the lowest temperature
of freezing dictate the extent of microbial damage
from ice crystal
Department of Food Science and Technology
Bogor Agricultural University
On freezing and thawing :
Microbial cell are found to suffer sublethal (repairable)
injury
Cell wall and cell membrane are injured
DNA strand break
Ribosomal RNA degradation
Inactivation/activation of some enzymes
Sublethally injured cell : injuries of structural and
functional are reversible
Lethally/dead cell : irreversible
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Department of Food Science and Technology
Bogor Agricultural University
Nature of Microorganisms
Some m.o. are capable of growing as low as10oC.
Many mesophilic and thermophilic bacterial cells can
be sublethally injured and many die with time at low
temperature above freezing.
Vegetative cells of m.o. can sustain sublethal injury
and die at temperatures below10oC.
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