Judul: Aplikasi Bakteriosin dari Pediococcus pentosaceus 2A2 Pada Udang Rebus untuk Menghambat Pertumbuhan Listeria monocytogenes
Abstrak: Penambahan antimikroba merupakan salah satu cara untuk mempertahankan umur simpan pangan. Bakteriosin yang dihasilkan Bakteri Asam Laktat (BAL) adalah antimikroba alami yang dapat diaplikasikan pada bahan pangan. Salah satu BAL penghasil bakteriosin adalah P. pentosaceus 2A2. Tujuan penelitian adalah untuk melihat potensi SBS bakteriosin P. pentosaceus 2A2 dalam bentuk supernatan bebas sel (SBS) yang diaplikasikan pada udang rebus dalam menghambat pertumbuhan L. monocytogenes. Produksi bakteriosin oleh P. pentosaceus 2A2 dilakukan dalam media molase selama 24 jam kemudian disentrifugasi, evaporasi, dan filtrasi membran hingga diperoleh SBS. Aktivitas antibakteri SBS terhadap L. monocytogenes diuji dengan metode difusi cakram kertas. Zona hambat yang dihasilkan oleh SBS adalah 9.30 ± 0.092 mm. Penelitian selanjutnya dilakukan terhadap udang yang direbus pada suhu 95oC. Sampel udang rebus diinokulasi dengan cara melakukan perendaman dalam kultur L. monocytogenes (105 cfu/g) selama 30 menit. Selanjutnya, sampel tersebut dibagi menjadi kontrol, sampel tanpa penambahan SBS, dan sampel yang diberi penambahan SBS dengan konsentrasi SBS:udang sebesar 1:10 dan 1:2. Sampel disimpan selama 4 hari pada suhu refrigerator (4-7oC). Penelitian menunjukkan bahwa penambahan SBS konsentrasi 1:2 dapat mereduksi total mikroba dan L. monocytogenes sebesar 1.09 log cfu/g dan 0.81 log cfu/g pada hari keempat sedangkan sampel tanpa penambahan SBS menunjukkan peningkatan total mikroba dan total L. monocytogenes dari hari pertama hingga hari keempat. Semakin tinggi konsentrasi SBS yang ditambahkan per gram udang, semakin tinggi kemampuannya sebagai antimikroba dan antilisteria. Penambahan SBS terhadap penerimaan organoleptik mempengaruhi karakteristik mutu warna dan rasa sampel, namun tidak menunjukkan perbedaan yang signifikan terhadap karakteristik mutu aroma, tekstur, dan secara keseluruhan (overall).
Keyword: bakteriosin, L. monocytogenes, molase, P. pentosaceus 2A2, udang rebus

Judul: Application of Lactobacillus rhamnosus IN13 and Lactobacillus plantarum IN05 on Catfish (Pangasius sp.) polluted by Listeria monocytogenes
Abstrak: Bakteri Asam Laktat (BAL) merupakan bakteri non patogen yang aman bagi manusia dan berpotensi sebagai biopreservatif karena dikategorikan sebagai generally recognized as safe (GRAS). Beberapa produk metabolisme yang dihasilkan oleh BAL memiliki kemampuan sebagai antimikrob ialah asam organik, hidrogen peroksida, diasetil dan bakteriosin. Senyawa antimikrob L. plantarum IN05 dan L. rhamnosus IN13 yang diisolasi dari makanan fermentasi inasua dikaji potensinya sebagai biopreservatif. Kebutuhan konsumsi ikan segar di masyarakat banyak diminati karena kandungan protein hewani yang tinggi. Ikan patin merupakan salah satu ikan yang banyak dikonsumsi masyarakat, namun memiliki kekurangan mudah mengalami kerusakan dan penurunan mutu. Hal ini disebabkan oleh L. monocytogenes yang memiliki kemampuan tumbuh pada suhu penyimpanan dingin (refrigerasi) bahkan mampu bertahan pada suhu penyimpanan beku. Penelitian ini bertujuan untuk mengaplikasikan dan membandingkan penggunaan senyawa antibakteri (supernatan bebas sel netral, supernatan bebas sel, dan biomassa sel bakteri) dari isolat L. rhamnosus IN13 dan L. plantarum IN05 serta formalin dalam penyimpanan ikan patin fillet yang terkontaminasi bakteri Listeria monocytogenes. Metode yang digunakan mencakup produksi senyawa antibakteri, penentuan sensitivitas senyawa antibakteri terhadap bakteri uji, uji konfirmasi senyawa antibakteri dengan penambahan proteinase K, aplikasi senyawa antibakteri pada ikan patin fillet, perhitungan total koloni bakteri, koloni bakteri L. monocytogenes, dan bakteri asam laktat, serta pengukuran nilai pH ikan patin fillet. Senyawa antimikrob SBSN dari L. rhamnosus IN13 memiliki kemampuan mempertahankan ikan patin fillet sampai lama penyimpanan 14 hari sesuai dengan syarat ikan segar yang layak untuk dikonsumsi. Nilai total mikrob 5.65 log CFU/g, nilai pH daging ikan patin fillet 6.37, dan nilai total bakteri L. monocytigenes yang menurun selama waktu penyimpanan., Lactic Acid Bacteria (LAB) are non-pathogenic bacteria that are safe for humans and have potential as biopreservatives because they are categorized as generally recognized as safe (GRAS). Several metabolic products produced by LAB have antimicrobial properties, namely organic acids, hydrogen peroxide, diacetyl and bacteriocins. Antimicrobial compounds L. plantarum IN05 and L. rhamnosus IN13 isolated from fermented inasua food were studied for their potential as biopreservatives. The need for consumption of fresh fish in the community is in great demand because of the high content of animal protein. Catfish is one of the fish that is widely consumed by the community, but it has the disadvantage of being easily damaged and decreasing in quality. This is due to L. monocytogenes which has the ability to grow at cold storage temperatures (refrigeration) and even survive at frozen storage temperatures. This study aims to apply and compare the use of antibacterial compounds (neutral cell-free supernatant, cell-free supernatant, and bacterial cell biomass) from L. rhamnosus IN13 and L. plantarum IN05 isolates and formalin in storage of catfish fillets contaminated with Listeria monocytogenes bacteria. The methods used include the production of antibacterial compounds, determination of the sensitivity of antibacterial compounds to test bacteria, confirmation test of antibacterial compounds with the addition of proteinase K, application of antibacterial compounds to catfish fillets, calculation of total bacterial colonies, bacterial colonies of L. monocytogenes, and lactic acid bacteria, as well as measurement of the pH value of catfish fillet. The SBSN antimicrobial compound from L. rhamnosus IN13 has the ability to maintain
Keyword: Bacteriocin, Biopreservatives, Lactobacillus rhamnosus, Listeria monocytogenes, pangas-catfish fillets

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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