Judul: Contamination of Escherichia coli in  Chicken Meat of Chicken Soto from Outlets Around the Campus of Dramaga IPB  University
Abstrak: Soto ayam merupakan salah satu makanan popular yang bisa menjadi ancaman serius pada kondisi kesehatan apabila daging soto ayam yang tercemar Escherichia coli terkonsumsi oleh tubuh. Penelitian ini bertujuan menghitung jumlah cemaran dan mengidentifikasi faktor keberadaan Escherichia coli pada sampel daging soto ayam dari gerai sekitar lingkar Kampus Dramaga IPB University. Sebanyak 30 sampel daging soto ayam diperoleh dari 10 pedagang soto ayam di lingkar Kampus Dramaga IPB University. Penelitian ini dilakukan dengan pengambilan kuesioner dari pedagang soto ayam serta pengujian jumlah Escherichia coli dengan metode most probable number dan dikonfirmasi dengan uji IMViC, serta pewarnaan Gram. Hasil penelitian menunjukkan rata-rata jumlah Escherichia coli pada daging ayam suwir soto ayam dari gerai sekitar lingkar Kampus Dramaga IPB University adalah 5,15 ± 3,56 MPN/g. Selanjutnya studi ini mendapatkan 90% (9/10) pedagang soto ayam teridentifikasi positif Escherichia coli pada daging soto ayam. Faktor yang memengaruhi keberadaan Escherichia coli yaitu lokasi penjualan dekat dengan jalan padat kendaraan, penyimpanan daging pada wadah terbuka dan suhu ruang, praktik pengolahan, tingkat kebersihan dari peralatan penyuwiran, serta penerapan higiene sanitasi yang kurang baik., Chicken soto is one of the popular foods that makes it possible to present a serious threat to health conditions if the shredded chicken soto contaminated with Escherichia coli consumed. The study aimed to calculate the number of Escherichia coli and identify the presence factors of Escherichia coli on chicken soto samples from the outlets around the campus of IPB University. A total of 30 samples of shredded chicken soto were obtained from 10 chicken soto sellers around the Campus of Dramaga IPB University. The study was conducted using a questionnaire of chicken soto sellers and the numbers of Escherichia coli was carried out using the most probable number method and was confirmed by IMViC test, and Gram stainning. The results of the study showed that the average amount of Escherichia coli in shredded chicken soto from outlets around the Campus of Dramaga IPB University was 5,15,
Keyword: Escherichia coli, cemaran, daging ayam, soto ayam

Judul: Detection of Escherichia coli in Chicken Noodle Soup Meat Sold in Dramaga Campus IPB University
Abstrak: Soto ayam merupakan masakan sup ayam Indonesia dengan kuah kuning yang terbuat dari kaldu ayam dan kunyit, serta bumbu lainnya. Hidangan ini terdiri atas potongan daging ayam yang dimasak, disajikan dalam mangkuk dengan tambahan lontong, tauge, kentang, telur rebus, bawang goreng, seledri, irisan jeruk nipis, dan pelengkap lainnya. Penelitian ini bertujuan mengidentifikasi jumlah bakteri Escherichia coli dan praktik higiene pada pedagang soto ayam yang dijual di dalam Kampus IPB, Dramaga. Sebanyak 30 sampel dikoleksi dari 10 pedagang soto ayam di dalam Kampus Dramaga IPB University. Pengambilan kuesioner terkait karakteristik pedagang soto ayam dan pengujian jumlah Escherichia coli dilakukan dalam penelitian ini dengan metode most probable number dan dikonfirmasi dengan uji IMViC serta pewarnaan Gram. Hasil penelitian menunjukkan sebanyak 70% (7/10) pedagang dengan jumlah sampel yang melebihi jumlah Escherichia coli > 3 MPN/g dalam pangan sebanyak 56,67% (17/30) tersebut teridentifikasi positif bakteri E. coli dengan jumlah rata-rata 8,84 ± 7,37 MPN/g. Keberadaan Escherichia coli pada soto ayam dipengaruhi oleh beberapa faktor seperti lokasi penjualan, waktu penyuwiran, penyimpanan daging, dan penerapan higiene sanitasi yang kurang baik. Selain itu, karakteristik pedagang seperti tingkat pendidikan, lama berjualan, dan tingkat pengetahuan dalam pengolahan ayam yang kurang baik dari pedagang soto ayam di kantin Kampus Dramaga IPB University., Chicken noodle soup is an Indonesian chicken soup dish with a yellow broth made from chicken stock and turmeric, as well as other seasonings. The dish consists of pieces of cooked chicken, served in a bowl with additional lontong, bean sprouts, potatoes, boiled eggs, fried onions, celery, lime wedges, and other accompaniments. This study aims to identify the number of Escherichia coli bacteria and hygiene practices in chicken soup vendors sold inside IPB Campus, Dramaga. A total of 30 samples were collected from 10 chicken noodle soup sellers in Dramaga Campus of IPB University. Questionnaires related to the characteristics of chicken noodle soup sellers and Escherichia coli count testing were conducted in this study using the most probable number method and confirmed by IMViC test and Gram staining. The results showed that 70% (7/10) of traders with the number of samples exceeding the number of Escherichia coli > 3 MPN/g in food, 56,67% (17/30) were identified as positive for E. coli bacteria with an average number of 8,84 ± 7,37 MPN/g. The presence of Escherichia coli in chicken noodle soup is influenced by several factors such as the location of sales, the time of cleaning, meat storage, and the application of poor sanitary hygiene. In addition, the characteristics of traders such as level of education, length of time selling, and level of knowledge in processing chicken are not good from chicken noodle soup traders at the canteen of Dramaga Campus of IPB University.
Keyword: chicken noodle soup, contamination, Escherichia coli, hygiene sanitation

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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