Judul: Kualitas mikrobiologis sosis daging sapi dengan penambahan bakteriosin sebagai bahan pengawet alami
Abstrak: One of the purposes of food preservation is to extend the self life of food. Nowadays, biological food preservation technology gets special attention from people. Beef sausage is one of meat product which is potential as medium for microbial growth. Many techniques have been applied to reduce microbial growth and to preserve the beef sausage. The most of preservation method use a chemical preservatives which can give healthy effect for human. Therefore, biopreservative is needed to replace chemical preservative. One of the biopreservative is bacteriocin produced by Lactobacillus plantarum 2C12. The aim of the research was to observe the microbiological characteristics of the sausage with the addition of preservatives (control, 0.3% nitrite, and 0.3% crude bacteriocin) at different storage time (0, 3, 6 and 9 day) in cold temperature (4-6 oC). The concentration of the protein produced from stages of cell free supernatan bacteriocin precipitates, and crude bacteriocin were 74 ± 18.38; 120.5 ± 7.78; 151 ± 2.83. This suggests that the protein concentration increased in each stage. Fresh meat purity test results showed that the total number of microbes is 2,19x104 cfu/g, Staphylococcus aureus 4.71x102 cfu/g, and 0.00 cfu/g for Escherichia coli and Salmonella spp. The quality of microbiologists sausage of beef show the total number of microbes that are contained in sausage of beef control, nitrite, and bakteriosin still in accordance with the safe limit consumption by SNI 01-3820-1995. Salmonella spp. and Eschirichia coli not found in beef sausage. Bacteriocin inhibits the growth of pathogenic bacteria especially Staphylococcus aureus in beef sausage. This shows that bacteriocin can replace the nitrite as a preservative with storage for six days at refrigerator temperature
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Judul: Karakteristik Mikrobiologis Sosis Sapi Yang Menggunakan Pengawet Antimikroba Dari Lactobacillus Plantarum 1a5 Yang Disimpan Pada Suhu Dingin
Abstrak: Beef sausage is a very well known food product. This product has very short shelflife. Therefore, save and consumptable preservation like biopreservation is needed. One of the biopreservation is LAB (Lactic Acid Bacteria) which produce antimicrobial substrate on it to preserve the beef sausage. The aim of the research was to observe antimicrobial effect from lactic acid bacteria to microbiological quality of beef sausage during storage in refrigerate temperature. The result showed that concentration of antimicrobial could reduce quantity of Total bacteria and E. coli significantly in refrigerate temperature until five days. Antimicriobial also could reduce S. aureus. In addition, Salmonella test produces negative result. Keywords : Beef sausage, antimicrobial substrate, biopreservation
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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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