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: Keberadaan Salmonella pada Daging Ayam yang Dijual di Pasar Tradisional di Kota Tangerang Selatan
Abstrak: This study was aimed to observe the presence of Salmonella in chicken meat sold in traditional markets in South Tangerang City. This research was conducted with survey method by interview the vendors of chicken meat as respondents, observation of markets condition using check-list, and sampling the chicken meat for Salmonella test. Total of 24 chicken meat samples was taken from three traditional markets, i.e., Modern Market, Bukit Market, and Jombang Market. The presence of Salmonella was performed using the isolation and identification test based on the Indonesian National Standard Number 2897:2008. The study showed that the Modern Market had the best criteria on the hygiene aspects compared to the other markets. The presence of Salmonella in chicken meat samples was 33.3% from Jombang Market (1 of 3 samples), 18.2% from Bukit Market (2 of 11 samples), and 10% from Modern Market (1 of 10 samples), with the total percentage of 16.7% (4 of 24 samples). The presence of Salmonella in chicken meat is associated with bad personal hygiene practices and the lack of cold chain from slaughterhouses to the markets. This condition requires attention from the government since Salmonella is the important foodborne pathogen that can threat the public health
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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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