Judul: Karakterisasi Bakteri Asam Laktat Termofilik dari Kawah Putih Gunung Pancar, Bogor
Abstrak: Lactic acid bacteria (LAB) commonly found in fermented dairy products are known to have advantageous effects for health. Thus, they can add the value of milk based products, such as yoghurt, cheese, and kefir. The aim of the study was to characterize thermophilic LAB on its ability to carry out metabolism at high temperature. Exploration of this bacteria was carried out at extreme environment of Indonesia as habitat for thermophilic, the White Crater of Mount Pancar, Bogor. Characterization of thermophilic LAB was conducted at pH of 3, 5, 7, and 9 with variation temperature at 30ºC, 45ºC, 60ºC, and 75ºC. Quantitative determination of bacteria was based on turbidimetry method, Plate Count, and analysis on ability of acid production in milk medium under optimum conditions at 45˚C and 60˚C for 60 hours with 12 hours intervals. Results showed that thermophilic LAB has optimum condition at pH 7 with incubation temperature between 45˚C-60˚C, and incubation period at the optimum number of cell was about 20 hours. The ability of acid production in milk medium at 45˚C-60˚C was 0.16%-0.27% after 12-24 hours. The study showed that there was thermophilic LAB present in the local environment and needs further identification.
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Judul: Karakteristik Pertumbuhan Bakteri Asam Laktat Indigenous Susu Sapi Segar Sebagai Kandidat Bakteri Probiotik Dalam Saluran Pencernaan in vitro
Abstrak: Functional foods in the form of probiotic yogurt serves as a food that provides health effects, especially in the digestive tract. This probiotic yogurt can maintain the balance the intestinal microflora, especially between beneficial and pathogen bacterials. Terms of the probiotic bacteria concerned to lactic acid bacteria that were able to survive at the digestive tract. The purpose of this study was to investigate the characteristics of lactic acid bacteria indigenous cow’s milk as a candidate of probiotic bacteria. Resistancy of lactic acid bacteria through different pH conditions, in presence of bile salts or antibiotics, were tested in the media that was conditioned as human digestive tract (in vitro). Lactic acid bacteria resistance was seen through a comparison of the original population before the treatment and the population after treatment. The results of this study, bacteria L. acidophilus Y-01, B. longum Y-01 and L. bulgaricus S-01 can be used as candidates probiotic bacteria because it survived in a pH condition (pH 2, 2,5, 3,2 and 7,2), the condition of bile salts, and antibiotics. Although the population of S. thermophilus S-01 and L bulgaricus S-01 decreased after treatment, all four of these bacteria also produce antimicrobial evidenced by the clear zone that formed around the supernatant. This antimicrobial activity showed inhibition to the growth pathogenic bacteria (E. coli, S. Typhimurium, and S. aureus).
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Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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