Judul: Pengujian Salmonella spp. pada Beberapa Produk Pangan Kering dan Uji Ketahanannya terhadap Proses Pengeringan
Abstrak: Some cases of salmonellosis because of consume fresh food products have been widely reported. Conditions of neutral pH, water content and nutrients in the food product are a suitable environment for growth of pathogenic bacteria, especially Gram-negative bacteria Salmonella. Dry processing is one of preservation techniques of food products are often used to prevent the growth of Salmonella. Some dried food product has a longer self live than fresh food products. Although dry conditions are less favorable environment for bacterial growth, but there are several strains of Salmonella that has been reported survive in dry conditions with low aw (0,2-0,5). A number of food borne pathogen (KLB) salmonellosis after eating dry food products such as milk powder, chocolate, chips, desiccated coconut and almonds contaminated by Salmonella has been reported in the United States and Europe since 1960. Data of Salmonella contamination on dried food products has not been reported in Indonesia. Under these conditions, the study was conducted to test for Salmonella spp. in several food products include dried skimmed milk powder, cocoa powder and desiccated coconut and tested for resistance in drying process. The method used in these testing of Salmonella spp. is the conventional method based on USFDA BAM (2007) and biochemical testing methods using API Test 20E. Selective enrichment media used were tetrathionate broth (TTB) and rappaport-vassiliadis (RV). Specific media used were hektoen enteric agar (HEA), bismuth sulfite agar (BSA) and xylose lysine deoxycholate agar (XLDA). Test results showed that selective enrichment media and agar media specific TTB and HEA able to confirm the positive expectations of Salmonella is more accurate than other selective media. Salmonella detection test results until the confirmation test (using urea broth media / UB) showed that some 29.6% of 27 samples of dried food products are analyzed, it was suspected positive Salmonella. The samples are two samples of cocoa powder, four samples of skimmed milk powder and two samples of desiccated coconut. All of the samples that are suspected positive Salmonella were samples using a low density polyethylene (LDPE) packaging that is not sealed and contained total microbial contaminant that exceeds SNI standards. Identification of suspected Salmonella using API Test 20E shows that the bacterial isolates from a suspected positive Salmonella sample is identified not 100% Salmonella. Isolate sample A9 (cocoa powder) has 15 biochemical properties similar with Salmonella spp. ATCC 14028. This shows that in the prediction rate 75%, isolates from samples A9 is Salmonella. The test results showed that the isolates from skim milk powder sample B4 75% identified as S. Paratyphi, isolates from samples of skimmed milk powder B9 85% identified as S. arizonae, isolates from skim milk powder sample B10 75% identified S. arizonae and isolates from skim milk powder sample B6 60% identified S. arizonae. While the desiccated coconut samples (C2 and C4) were identified not Salmonella, because of the negative reaction with glucose. Treatment for resistance testing of Salmonella in dry processing includes the process of oven drying temperature 90oC for 4 hours and 5 hours and the oven drying temperature 90oC- 110oC for 3 hours and 3
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Judul: Isolasi Salmonella Spp. Pada Sampel Daging Sapi Di Wilayah Bogor Serta Uji Ketahanannya Terhadap Proses Pendinginan Dan Pembekuan
Abstrak: Nowadays people must be aware to their choose of food, due to many case affected by salmonella contamination. This research focusing on level of salmonella contamination in beef samples and its survival ability at frozen (-16°C) and refrigeration (6°C) temperature. Beef samples (ground and cut) was collected from 5 traditional market and 10 modern market in Bogor area. The contamination level was determined by aerobic plate count method and conventional isolation of Salmonella spp. The average of aerobic plate count from traditional market was 7.49 ± 0.49 log CFU/g and from modern market was 6.09 ± 0.85 log CFU/g. Meanwhile, the isolation level of Salmonella spp. with API 20E from total 30 samples reach 16.67%. One sample was indicated 99.9% (excellent identification) of Salmonella spp. while the other 4 samples was indicated 89.4% (excellent identification). Salmonella spp. in beef samples kept at -16°C and 6°C show that it was good to survive in both temperature, no matter first inoculum in 3 log CFU/g or 6 log CFU/g. Its survival ability can be seen from insignificant change of total Salmonella spp. counted (p>0,05).
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Judul: Solusi Geometri Schwarzschild untuk Dimensi 4+1 dengan Invarian Rotasi Isotropik
Abstrak: Metrik Schwarzschild merupakan solusi eksak pertama dari persamaan medan Einstein dengan mangasumsikan metrik statik dan simetris. Metrik Schwarzschild yang ditemukan oleh Karl Schwarzschild masih dalam dimensi 3+1, namun seiring dengan teori-teori terbaru yang menunjukkan bahwa alam semesta tidak hanya di dimensi 3+1. Maka melalui penambahan dimensi, tujuan penelitian ini memperoleh solusi pada geometri Schwarzschild untuk dimensi 4+1 dengan memodifikasi koordinat bola yang invarian rotasi isotropik dan melalui penurunan rumus seperti koordinat bola, simbol Christoffel, dan tensor Ricci. Selain mendapatkan solusi ini, metrik Schwarzschild dimensi 4+1 dapat digunakan sebagai metrik dasar untuk memperoleh solusi blackhole dan wormhole pada dimensi 4+1. Hasil akhirnya, dengan memanfaatkan modifikasi koordinat bola, metrik Schwarzschild dapat dibentuk sehingga diperoleh solusi geometri Schwarzschild untuk dimensi 4+1.
Keyword: metrik Schwarzschild, persamaan medan Einstein, modifikasi koordinat bola, penambahan dimensi, invarian rotasi isotropik