Mikrobiologi Pangan – Teknologi Pangan Universitas Muhammadiyah Semarang (UNIMUS)

PENDAHULUAN
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PERLU
PENCEGAHA
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PENDAHULUAN
Bahan pengawet

senyawa yg mampu menghambat dan
menghentikan proses fermentasi,
pengasaman atau bentuk kerusakan
lainnya dan dapat memberikan
perlindungan bahan pangan dari
pembusukan.

TUJUAN PENGGUNAAN PENGAWET
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SIFAT ANTIMIKROBIA

Menghambat pertumbuhan mikrobia dg cara:
1. Gangguan sistem genetik

2. Menghambat / mengganggu dinding sel ataupun membran sel

3. Pennghambatan enzim

4. Pengikatan nutrient esensial

PERSYARATAN BHN
PENGAWET YG BAIK
1. Memiliki arti ekonomis dr pengawetan
2. Hanya digunakan jika cara pengawetan tdk

mencukupi
3. Memperpanjang umur simpan
4. Tidak menurunkan kualitas
5. Mudah dilarutkan
6. Aman dlm jmlh yg diperlukan
7. Mudah dianalisis

8. Tidak menghambat enzim pencernaan
9. Tidak bersifat toksik
10.Spektra antimikrobia yg luas.

JENIS BAHAN PENGAWET
PENGAWET ORGANIK

terdiri dari asam-asam organik dan garamnya,
seperti asetat, benzoat, propionat, sorbat,
epoksida, dll.
PENGAWET ANORGANIK

- digunakan dlm bentuk garam seperti nitrit,
metabisulfit
- dalam bentuk gas seperti sulfit (SO2)
- dalam bentuk liquid seperti hidrogen peroksida

Pengawetan
Mencegah/menghambat fermentasi, pengasaman atau

penguraian lain thd makanan yg disebabkan oleh
mikroorganisme
Ditambahkan pd makanan yg mudah rusak (daging,
buah2an)
Contoh :
 As benzoat utk menghambat pertumbuhan bakteri,
ragi, jamur pd buah2an, minuman, ringan, sirup, kecap
(500 mg – 1 g/kg)
 As sorbat menghambat pertumbuhan jamur dan ragi
(roti, buah kering 250 mg-1 g/kg)
 As propionat menghambat pertumbuhan jamur (adonan
roti : 2 g/kg adonan roti)

ORGANIC ACID
Commonly used as antimicrobial preservative or

acidulan
The activity related to pH and generally limited to
pH < 5,5
Mechanism:

- organic acid influence cell walls synthesis in
prokaryotes.
- organic acid likely act at the cytoplasmic
membrane level. Organic acid penetrates the cell
membrane bilayer, and once inside the cell it
dissociates because the cell interior has a higher
pH than exterior.

a. Acetic acid & acetate
salt
More effective against yeast & bacteria
The activity depend on product, environment, and

microorganism.
Application:
- addition of acetic acid at 0,1% to scald tank
water used in poultry processing ddecrease the
salmonella & campylobacter (okrend et al., 1986)
- used as a spray sanitizer on meet carcases
effective for beef, lamb, & catfish fillets. Use of 2

% acetic acid resulted reduction in viable E. coli.
- added at 0,1% to bread dough inhibited growth
bacillus subtilis in wheat bread (pH 5,14) > 6
days.

Sodium acetate is an inhibitor of rope-forming

bacillus in baked goods and of the mold.
It is useful in the baking industry because t
has little effect on the yeast used in baking.

b. Benzoates & other
Primary uses as antimycotic agent (most yeast

and mold)
Benzoates are most effective at pH 2,5 – 4,0.
Mechanism: benzoic acid destroyed the proton
motive force of the cytoplasmic membrane by
continous transport of proton into the cell causing
disruption of the transport system.

Benzoates also inhbit enzymes in bacterial cell as
those controlling acetic acid metabolism &
axydative phosphorylation.
Benzoates had no carcinogenic effect were given 1
– 2% and nonmutagenic.

Other organic antimikrobial
agents
Lactic acid is primary used to many

fermented diary, vegetable, and meet
product. It is usually used as a food additive
for pH control & flavoring.
Propionic acid & propionate use to against
mold, yeast, & bacteria gram negative.
Usually used in baked goods & cheese.
Sorbic acid & sorbates have been used in food
as effective inhibitor of fungi, including that
produce mycotoxin, and certain bacteria.

NITRITES
Nitrite salt (KNO2 & NaNO2 ) primarily used to

inhibit the growth and toxin roduction of C.
botulinum in cured meats.

Nitrite is most inhibitory to bacteria at acidic

pH and more inhibitory under anaerobic
condition

Mechanism: the inhbitory effect f nitrite on

bacterial sporeformers is apparently due to
inhibition of outgrowth and during cell division.

Nitrite does not inhibit spore germination

to a significant extend. Nitrite inactivated
enzymes associated with respiration .

Lethal dose of nitrites in human is 2 – 6 g,

prolonged ingestion nitrite cause
methemioglobinemia, that is, excessive
production of abnormal mioglobin.

NATAMYCIN
Natamycin or pimaricin ( C33 H47 NO13 )is a polyene

macrolide antibiotic.
Natamycin is active against nearly all molds and yeast,
but no effect on bacteria or viruses.
Several factors affect the stability & resulting
antimycotic activity of natamycin:
-pH, 100% natamycin activity is retained at pH 5 - 7
-temperature, high temperature will decrease activity
-light,
-oxidant,
-heavy metal.

Mechanism: polyene macrolide antibiotic is

binding to ergosterol & other sterol group of
the fungal cell membrane.
Generally, binding of the natamycin by sterol
causes inhibition of ergosterol biosynthesis
and distortion of the cell membrane with
resultant leakage.
Application: cheese, baking industry, fruits,
and meets as a mold spoillage inhibitor.

DIMETHYL DICARBONATE
(DMDC)
The primary target microorganism for DMDC

are yeast.
It was more effective than sorbate &
benzoate. Mold are generally more resistant to
DMDC than yeast or bacteria.
DMDC used in product: wine, teas, carbonated
& noncarbonated juice beverages, and
carbonated & noncarbonated nonjuice
beverages.


Other antimicrobial
agents
Lysozyme (1,4-β-N-acetylmuramidase),

catalyzes hidrolysis peptidoglican of bacterial
cell walls.
Nisin, peptide produced by a strain of dairy
starter cultur L. lactis
Phosphates
Sulfites

Pelanggaran
Penggunaan
Pengawet
Menggunakan bahan pengawet yang dilarang

penggunaannya untuk pangan.
Menggunakan pengawet melebihi dosis yang
diizinkan.

PENGAWET DILARANG
Formalin (pengawet mayat)
Asam Borat (Boric Acid) dan senyawanya
Antibiotik (Chloramphenicol)
Asam Salisilat dan garamnya (Salicylic Acid and

its salt)
Dietilpirokarbonat (Diethylpirocarbonate DEPC)
Kalium Klorat (Potassium Chlorate)
Kalium Bromat (Potassium Bromate)
Nitrofurazon (Nitrofurazone)