Judul: Isolasi, identifikasi dan evaluasi karakteristik bakteri pembentukan histamin dari pindang ikan tongkol
Abstrak: Pindang merupakan salah satu produk tradisional Indonesia yang sampai saat ini mutu dan keamanannya masih kurang diperhatikan. Salah satu bahaya yang dapat terjadi akibat penanganan dan higienis yang kurang baik selama proses produksi, pengemasan, distribusi, pemasaran atau penyimpanan ikan pindang adalah terjadinya kontaminasi oleh bakteri-bakteri pembentuk histamin, karena umumnya selain membentuk senyawa racun, bakteri-bakteri ini bersifat patogen. Salah satu cara untuk mencegah terjadinya kontaminasi oleh bakteri-bakteri pembentuk histamin adalah mengetahui jenis-jenis dan sifat-sifat bakteri ini sehingga dapat diu- sahakan alternatif untuk perbaikan proses. Dalam penelitian ini dilakukan isolasi, identifikasi dan evaluasi karakteristik bakteri pembentuk histamin dari pindang ikan tongkol. Penelitian ini dilakukan dalam tiga tahap. Tahap per- tama adalah pengamatan terhadap perubahan kualitas pindang ikan tongkol selama penyimpananan (0, 1, 2, 3, 4 hari) yaitu dengan mengamati perubahan kandungan total mikroba, bakteri pembentuk histamin, nilai TVN dari nilai pH. Tahap kedua adalah isolasi dan identifikasi bakteri pembentuk histamin dan tahap ketiga adalah mengamati sifat-sifat pertumbuhan bakteri terhadap suhu, pH dan konsentrasi NaCl. Hasil yang diperoleh menunjukkan bahwa selama penyim panan terjadi penurunan mutu dari pindang ikan tongkol, yaitu dengan meningkatnya total mikroba, bakteri pembentuk histamin, nilai pll dan nilai TVN. Pada hari keempat pindang sudah tampak berlendir dan berkapang…dst
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Judul: Perubahan Kadar Histamin dan Bakteri Penghasil Histamin dari Pindang Badeng Tongkol (Auxis rochei) Selama Penyimpanan
Abstrak: Pindang is an intermediate moisture product which is highly perishable if its handling and processing are not sufficient. The deterioration caused by the activities of microbes and enzyme produce biogenic amine compounds. The compounds creates from decarboxilation of amino acids in fish. One of the biogenic amine compounds is histamine. The high accumulation of histamine in fish is harmfull if consumed. The objective of this research was to analyze the storage effect of the histamine content and histamine-producing bacteria from the boiled tuna (Auxis rochei). This research was conducted in December 2013 to April 2014. Fresh fish tuna obtained from one day fishing by mini purse seine in TPI Cisolok Palabuhanratu. This research was devided into two stages; the first stage was keeping fresh tuna in 0, 8, 16, 24, 32 hours as control and test of organoleptic, TPC, TVB and histamine levels. The second stage of the research composed of three steps. The first step was boling fish in 25% salt addition at different time (2, 5, and 8 hours), then histamine test and determination of bacterial count. The best results of the first step continued to the second step. The second step, boiled fish were storaged at room temperature in 0, 8, 16, 24, 32 hours and its organoleptic value, histamine, TPC and TVB were analyzed. Sample with highest histamine content were analyzed in step 3, in which the histamine-producing bacteria were selected and identified. The influence of pH, temperature and NaCl concentration to the bacterial growth, histamine production were determined. Each species of bacteria was inoculated in boiled fish and its bacterial count analyzed. The results showed that storaging of fresh fish at room temperature caused in increasing of histamine, TVB levels and microbial activity. The histamine level didn’t lose after boiling and its level were increase during storage at room temperature. Histamine level were increase after storage time 8 hours and was haighly different with fish without storage treatment (p<0.05). Its level continued until 32 hours storage time. Bacterial count increased significantly after 24 hours (p<0.05). Its TVB-level increased significantly at 8 hours storage time and continue until 32 hours storage time. Boiled fish at 32 hours storage time shown 6 bacterial isolate and were expected as P. vulgaris, H. alvei, M. morganii, E.aerogenes, K. oxytoca, K. pneumoniae. Test on the abbility of 6 bacterial isolate to form histamine shown that K. pneumoniae produced the highest histamin level (132 mg/kg), while H. Alvei formed the lowest histamine level (78 mg/kg).
Keyword: Histamine, bacterial, pindang tuna (Auxis rochei)

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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