Judul: IPB (Bogor Agricultural University)
Abstrak: Through a nutritional improvement project, Bogor District had donated powdered milk formula (PMF) for severe malnutrition children below five years. Powdered milk formula was assumed as an unsterilized product, because it might contain microbes. To evaluate the bacterial contaminant, forty eight samples of donated PMF were taken proportional from ten Puskesmas in Kabupaten Bogor. To evaluate the home prepared milk formula, 50 samples of PMF, reconstitution formula, drinking water, drinking equipment, and hand swabs, was taken from the mothers. To evaluate the knowledge, attitude and behavior of the safety of reconstituted and home storage of PMF, 50 questioners were given to the mothers. Microbe samples were analyzed for total aerobic plate counts, Bacillus cereus and Clostridium perfringens. The median counts for total aerobic count were 4.7 x 102 CFU/g. The value of total aerobic count less than 1 x 104 CFU/g is used as a basic standard for baby food (SNI 01-7111.1-2005). Approximately 30.6% products were contaminated by B. cereus with a median count 1.4 x 102 CFU/g. The presences of C. perfringens in all samples were not detected. Australian and New Zealand Food Standard (Standard 1.6.1-Microbiological Limit for Food 2001) for follow-on milk formula were used as a basic standard for of B. cereus and C. perfringens and the acceptance number of B. cereus were 102 CFU/g and C. perfringens <1 CFU/g. All of the follow-on milk formulas were safe to be distributed and consumed. Attention must be taken, because 4 samples (26.7%) contained B. cereus was able to produce enterotoxin. Improper home storage could promote the growth of aerobic microbe and B. cereus. Improper preparation would promote the growth of B. cereus which present initially at low level (mean 7.8 x 10 CFU/g) and became 1.6 x 103 CFU/ml after the reconstitution had done. C. perfringens emerge at 4 samples (mean 1.5 x 10 CFU/ml) after the reconstitution. Several isolate of B. cereus (4 from PMF, 13 from opened PMF, and 2 from reconstitution formula) showed a possibility to produce diarrheagenic enterotoxin while the isolate of C. perfringens did not show it. The spore of B. cereus and C. perfringens could survive in different preparation temperature (25, 35 and 70oC for B. cereus and 25, 47, 70oC for C. perfringens) and storage abuse (with <50 and >70% humidity; opened, closed and opened twice a day in observation). Bacteria population increased .1 log within 3 hours at room temperature (28-29oC). The microorganism could survive from dry condition, especially when aw of the formulas increased cause of storage abuse. The result from questioners and microbe samples shown, that mothers knowledge of milk safety were correlated to the number of their children (r=-0.34). The carefullness attitude of mothers were correlated to the knowledge of milk safety (r=0.51), the family income (r=0.28) and the number of their children (r=-0.40). The healthy behaviour of mothers were correlated to knowledge of milk safety (r=0.31), the family income (r=0.37), and carefulness attitude (r=0.30). It is suggested, that changing mothers knowledge of milk safety are necessary.
Keyword: Enterotoksin, Powdered milk formula, Storage and preparation, West Java

Judul: IPB (Bogor Agricultural University)
Abstrak: UHT (Ultra High Temperature) is a thermal process given to milk in excess of pasteurization with time and temperature combination capable of rendering the product commercially sterilized. This research describe the microbiological study of imported UHT milk product in Indonesia. Thirty samples of UHT milk products were tested with several assays. The UHT process perfection test (Aschaffenburg test), the antibiotic detection test through Blaettchen assay and Yoghurt test, Total Plate Count assay for microbial counting, and Bacillus cereus confirmation test. B.cereus is an aerobic sporeformer that is commonly contaminate milk. B.cereus also could survive through heating process during UHT treatment. There were also report from Brazil on 1998 about a study where 34,17 % samples of UHT milk products have been detected positive for B.cereus contamination. The results of this research on imported UHT milk products showed 53,33% of the samples were true UHT milk, and 46,67% were sterilized milk The antibiotics residue test showed all of the samples did not contain antibiotics. The microbial detection test showed 20 samples (66,7%) of the 30 samples were contaminated by microbe. The B.cereus test showed 13,33% of the samples have been detected for B.cereus contamination
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf