kerusakan sel akibat denaturasi protein, sehingga sel menjadi lebih tahanresistance terhadap perlakuan panas atau peningkatan suhu.
5.2 Saran
Perlu dilakukan penelitian lebih lanjut mengenai perubahan seluler yang terjadi pada isolat lokal Cronobacter spp. yang mampu bertahan survive selama
proses pengeringan semprot sehingga mengalami peningkatan ketahanan terhadap suhu rekonstitusi 50 °C. Perubahan seluler pada isolat lokal Cronobacter spp.
yang mampu bertahan selama penyimpanan pada kondisi a
w
susu bubuk yang berbeda RH berbeda juga perlu diketahui. Perubahan-perubahan tersebut antara
lain kebocoran sel yang diindikasikan dengan meningkatnya jumlah asam nukleat dan protein dalam medium pertumbuhan Cronobacter spp., kemampuan tumbuh
dan bentuk kurva pertumbuhan Cronobacter spp. pada kondisi pH, suhu, dan tekanan osmosis berbeda, serta komponen solut seperti trehalosa yang
diakumulasi di dalam sel Cronobacter spp. selama mengalami stres pengeringan dan kekeringan.
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Lampiran 1. Tahapan Penelitian, Tujuan dan Rancangan Percobaan No
Tahapan Penelitian
Tujuan Faktor
AnalisisPengamatan
1. Konfirmasi kultur
Cronobacter spp. pada media
selektif DFI dan pada media TSA
Untuk mengetahui tingkat kemurnian
dan sifat-sifat Cronobacter spp.
yang digunakan -
Morfologi - pewarnaan Gram
- bentuk dan warna
koloni
2. Skrining cepat ketahanan panas
isolat Cronobacter spp.
pada suhu rekonstitusi 50 °C
selama 30 menit Untuk mendapatkan
1 isolat Cronobacter spp.
yang paling tahan pada suhu
rekonstitusi 50 °C selama 30 menit
Jenis isolat Cronobacter
spp. Log reduksi
Cronobacter spp.
3. Sintas Cronobacter sp. ,
dalam susu skim saat rekonstitusi
sebelum mengalami proses
pengeringan semprot
Untuk mengetahui sintas survival
Cronobacter sp. dalam skim milk saat
rekonstitusi sebelum mengalami proses
pengeringan semprot -
1. Log reduksi Cronobacter sp.
2. Pengamatan morfologi
- pewarnaan gram - bentuk koloni dan
- ukuran sel
4. Pengaruh pengeringan
semprot suhu inlet 160°C dan
outlet 82°C terhadap sintas
Cronobacter sp. Untuk mengetahui
pengaruh pengeringan semprot
terhadap sintas Cronobacter sp.
1. Jumlah Log Reduksi jumlah
Cronobacter sp. 2. a
w
aktivitas air 3. Kadar air awal susu
bubuk
5. Pengaruh pengeringan
semprot suhu inlet 160°C dan
outlet 82°C terhadap sintas
Cronobacter sp. saat rekonstitusi
Untuk mengetahui pengaruh
pengeringan semprot terhadap sintas
Cronobacter sp. saat rekonstitusi
1. Log Reduksi Cronobacter sp.
2. Pengamatan morfologi
- pewarnaan gram - bentuk koloni dan
- ukuran sel
No Tahapan
Penelitian Tujuan
Faktor - faktor
AnalisisPengamatan
6. Pengaruh RH penyimpanan
terhadap sintas Cronobacter sp.
Untuk mengetahui pengaruh RH
penyimpanan terhadap sintas
Cronobacter sp. 1.
RH penyimpan
an 50, 70, dan
90 1.
Junlah Cronobacter sp.
2. a
w
aktivitas air 3. Kadar air awal susu
bubuk 7. Pengaruh RH
penyimpanan terhadap sintas
Cronobacter sp. saat rekonstitusi
Untuk mengetahui pengaruh RH
penyimpanan terhadap sintas
Cronobacter sp. saat rekonstitusi
2. RH
penyimpan an 50,
70, dan 90
1. Log reduksi Cronobacter sp.
2. Pengamatan morfologi
- pewarnaan gram - bentuk koloni dan
- ukuran sel
Lampiran 2. Hasil Konfirmasi Isolat Cronobacter spp.
1. Aktivasi kultur stok Cronobacter spp. dalam medium BHI broth
2. Pewarnaan gram Mikroskop Cahaya Perbesaran 1000x
3. Konfirmasi 8 isolat Cronobacter spp. dalam media selektif DFI Agar
4. Konfirmasi 8 isolat Cronobacter spp. dalam media TSA Agar
Lampiran 3. Proses Pengeringan Semprot dengan Spray Drier Suhu Inlet ±160
°C Suhu Outlet ±82 °C
Susu skim hasil pengeringan semprot suhu inlet 160°C dan outlet 82°C
a b
Bentuk koloni Cronobacter spp. YRc3a dalam media TSA-YE sebelum a
dan sesudah pengeringan semprot b
Lampiran 4. Hasil Perhitungan Sintas Cronobacter spp. YRc3a Selama
Proses Pengeringan Semprot
1. Jumlah inokulum hasil sentrifugasi ± 10
11
cfuml 3000 rpm15 menit
Ulangan Jumlah Inokulum biomasa sel
Pengenceran ∑ koloni
CFUml
I -8 TBUDTBUD
4.05x10
11
3.46 x 10
11
-9 9189 -10 48
II -9 224188
2.41 x10
11
-10 6751 -11 105
2. Reduksi jumlah sel setelah mengalami proses pengeringan semprot jumlah
awal sel merupakan jumlah sel awalbiomasa sel. a.
Jumlah awal sel yang diinokulasikan ± 2 ml biomasa sel dalam BPW dimana:
- Jumlah selml 3.46 x 10
11
cfuml Total jumlah sel yang diinokulasikan 6.92 x 10
11
cfu 2 ml
- Jumlah sel setelah diinokulasikan dalam 450 ml 180 gram270 ml
dalam ml aktualnya pada tabel berikut :
Ulangan Jumlah Sel dalam 450 ml skim milk
Rata-rata CFUml
Pengenceran ∑ koloni
CFUml
I -7
2922 2.55x10
8
2.2 x10
8
-8 47
-9 10
II -7
2314 1.85 x10
8
-8 51
-9 10
- Jumlah sel dalam gram skim milk 180 gram = 3,84 x 10
9
CFUg
b. Hasil pengeringan semprot sebanyak ± 45 gram hasil analisa survival sel
dalam skim milk yang direkonstitusi 2.2 gram 15 ml adalah :
Ula Ngan
Survivor 27
o
C: ± 1menit Rata-
rata CFU
ml ∑ koloni
Survivor 50
o
C: ± 1menit Rata-
rata CFU
ml Pengen
Ceran ∑ koloni
Pengen ceran
Pengen ceran
∑ koloni CFU
ml
I -3
3515 2.5 x10