Judul: Cemaran Staphylococcus aureus pada Daging Ayam yang Dijual di Pasar-Pasar di Tangerang Selatan
Abstrak: The aim of this study was to observe the total of Staphylococcus aureus in chicken meat sold in markets in South Tangerang City. This study was conducted using survey method by interviewing the vendors of chicken meat as respondents and observation the condition of marketplaces using questionnaires and sampling the chicken meat for laboratory examination. Total of 24 chicken meat samples was obtained purposively from 3 traditional markets, i.e., Pasar Modern, Pasar Bukit, and Pasar Jombang, and was examined with the spread plate method (the plate count method). The result of observation showed that Pasar Modern had the best criteria of general hygienic practices. Nevertheless, the laboratory result found that the chicken meat samples from Pasar Modern showed the highest amount of S. aureus (1116.0 + 1461.0 cfu/gram) and it was followed by Pasar Bukit (618.2 + 1045.8 cfu/gram) and Pasar Jombang (433.3 + 665.8 cfu/gram), with the mean of 802.5 + 1194.2 cfu/gram. Compared to the maximum limit of microbial contamination according to the Indonesia National Standard (SNI 7688:2009), 80% of chicken samples from Pasar Modern were higher than the standard (maximum limit = 100 cfu/gram), and then 66.7% of samples from Pasar Jombang and 54.5% of samples from Pasar Bukit were higher than the standard. The high number of S. aureus contamination in chicken meat was supposed in relation with inadequate personal hygiene practices and lack of cold chain from poultry processing plant until marketplace. This condition should be considered as a risk of food intoxication for the consumers since the presence of S. aureus in food in high number could produce the toxin which is heat-stable.
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Judul: Cemaran Eschericia coli pada Daging Ayam di Pasar Tradisional Kota Tangerang Selatan
Abstrak: The aim of this study was to observe the total count of Eschericia coli in chicken meat in tradisional markets in South Tangerang City. This study was conducted using survey method by interviewing the vendors of chicken meat as respondents, observing the condition of marketplace using questionnaires, and sampling the chicken meat for laboratory examination. A total of 24 chicken meat samples was obtained purposively from three markets, i.e., Pasar Modern, Pasar Bukit, and Pasar Jombang, and was examined using spread plate method (plate count method). The result of the study showed that Pasar Modern had the best criteria of general hygienic practices. Nevertheless, the laboratory result found that the chicken meat samples from Pasar Jombang showed the highest number of E. coli (5.59 ± 5.64 log10 cfu/gram) and it was followed by Pasar Modern (5.38 ± 5.59 log10 cfu/gram) and Pasar Bukit (5.11 ±5.39 log10 cfu/gram), with the mean of 5.40 ± 5.55 log10 cfu/gram. Compared to the maximum limit of microbial contamination according to the Indonesia National Standard (SNI 7688:2009), 100% of chicken samples from Pasar Jombang were higher than the standard (maximum limit = 1 log10 cfu/gram), and then 100% of samples from Pasar Modern and 100% of samples from Pasar Bukit were higher than standard. The high number of E. coli contamination in chicken meat was supposed in relation with market sanitation, proces eviceration, cross contamination with other food, inadequate personal hygiene practices and lack of cold chain from poultry processing plant until market place.
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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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