Agar, one of the most abundant marine products has not been utilized extensively because of low level of processing technology in Korea. This research was carried out to improve the utilization of agar and consequent increase in profit. Antibacterial activity of agarooligosaccharides were evaluated against bacteria causing putrefaction and food poisoning. Addition of 0.4% agarooligosaccharides showed antibacterial activity toward Staphylococcus aureus and Escherichia coli O157:H7; furthermore, autoclave treatment of agarooligosaccharides solution enhanced the antibacterial activity. Agarooligosaccharides showed high stability against the pH change. Addition of amino acid(alanine, lysine, glycine, phenylalanine) in agarooligosaccharides solution enhanced antibacterial activity in E. coli O157:H7, Streptococcus mutans and Staphylococcus aureus.
Agarooligosaccharides were produced by β-agarase from Bacillus cereus ASK 202. LD_(50) of Agarooligosaccharides was determined to be 1359 mg/kg which corresponded to GRAS material. Agarooligosaccharides at 5% level exhibited 88.3% inhibition on TA98 and 54% on TA100, indicating agarooligosaccharides to be potent antimutagenic substance. Immunologic activity of agarooligosaccharides was also confirmed by mouse spleen cell culture. Agarooligosaccharides addition of 200 ㎕/ml stabilized spleen cells (2.5 × 10^6 cells/ml) as compared to control (6.4 × 10⁴ cells/ml).
The toxicity and toxin composition between blue mussel, Mytilus edulis and oyster, Crassostrea gigas collected at Woepori in Koˇ je island in South Coast of Korea in 1996 and 1997 were compared. The highest toxicity score was about 10 times higher in blue mussel than oyster (blue mussel, 8,670 ㎍; oyster, 860 ㎍ in 1996, blue mussel, 5,657 ㎍; oyster, 531 ㎍/100 g in 1997). The blue mussel also retained its toxicity for slightly longer period than oyster. In the both shellfish, PSP was composed almost exclusively of C toxins (C 1 and C2, 2065%) and gonyautoxins (GTX1, 2, 3 and 4, 38-78%). In the early period of toxin accumulation, the ratio of 11(3-epimer toxins (C2, GTX4) whose amount was 2556 mole% (5th March to 12th April in 1996) and 2580 mole% (18th March to 7th April in 1997), were higher than that of llα-epimer toxins (C1, GTX2) in both shellfish. As the lapse of intoxification time, however, the ratio of 11-epimer toxins (C1, GTX2) whose amount was 41-57 mole% (27th May to 3rd June in 1996) and 25-56 mole% (29th April to 12th May in 1997), became higher than that of 11-epimer toxins. The toxin compositions in the both samples changed on a daily basis, presumably owing to metabolism of the toxins in the bivalves.
Paralytic shellfish poison (PSP) occurrence and variation in the different bivalve species including oyster, Crassostrea gigas and mussel, Mytilus edulis in Jinhae bay Korea from January to December in 1997 were surveyed. And also compositional characteristics of PSP ingredients in the different bivalve species were investigated. PSP in shellfish was detected from late February and increased continuously until the middle of April in Jinhae bay. And after April PSP level had been decreased gradually and the toxicity was not detected by mouse bioassay in the early of June. Of the examined bivalve species, PSP content in the mussel exhibited the highest value and the PSP content in the mussel in the middle of April, PSP high season in Jinhae bay, was 6 times higher than that in the oyster. Gonyautoxin (GTX)1-4 group occupied 59.0-78.8% of whole PSP contents and identified as dominant ingredient in the examined bivalves except oyster. And it is also identified that the PSP toxicity in the tested species were derived from the GTX group. And the dominant ingredient of PSP in the oyster was carbamoyl-N-sulfo-llα- hydroxysaxitoxin sulfate(C1)(37.9%) and neosaxitoxin(neoSTX)(26.2%). But the toxicity of C1 in the tested oyster could be ignorable and most toxicity (80.0%) was derived from saxitoxin (STX) group.
Gamma irradiation at 20 kGy was applied to Kanjang (soy sauce), Doenjang (soybean paste), Kochujang (hot pepper paste) and Chungkukjang for their possible genotoxicity The genotoxicity of 20 kGy-irradiated samples was evaluated by Salmonella typhimurlum reversion assay. The Salmonella tester strains included TA98, TA100, TA1535 and TA1537 in the absence and presence of an exogenous metabolizing system (S9 mix). All samples were negative in the bacterial reversion assay with S. typhimurium TA98, TA100, TA1535 and TA1537. The results indicated that 20 kGy of gamma irradiation on water-soluble fraction of Kanjang, Doenjang, Kochujang and Chungkukjang were not shown mutagenicity.
Following the recent policy, enlargement of foodservice and contracted management systems of high school foodservices have been accelerated, and the scales of foodservices have been gradually increased. A sudden growth of domestic foodservice companies have remarkably disparated. Yet compared to that of the foodservice control in advanced countries, domestic foodservice control has a lot more to learn. Due to the characteristics of foodservice establishment serving many people at a time, there is always a high potential of food borne outbreak. The purpose of this study was to evaluate hazard factors in the steps of production, holding and assembly and service of fried curry hair-tail, cold seaweed and cucumber, fried pork cutlet, that were served by contracted management in high school foodservice centre, then to suggest method of control with the Hazard Analysis Critical Control Point(HACCP) program. Also we suggested the possibility that the contracted management of foodservice system can be established and utilized to identify the variation of holding temperature among foods up to 6 hours after cooking. The results are as follows; The hazard factors in food product had come from the temperature, time, pH, Aw, equipment and utensils. The critical control point(CCP) of each food product; curry hair-tail, cold seaweed and cucumber and pork cutlet was cooked and held before serving, prepared and held before serving, cooked and held before serving, and prepared, cooked and held before serving, respectively.
Serious consequences can arise from lack of hygiene in mass catering. Microbiological testing is of value in determining hazards for developing a HACCP plan, and in demonstrating to food handlers the reality of the microbial risk. This studies was performed to describe the overall hygiene of cooking utensils and equipments, employees, and environment in mass catering establishments. Generally, hygienic conditions of cutting board and sanitized dish cloth were better than those of other cooking utensils such as knife, sieve, and peeler. It was found that the cross-contamination of knife might be caused by the use of contaminated sanitizing solution. It was observed that there was considerable variation (10¹-10^5 CFU) of the number of general bacteria for employee's hands. The number of general bacteria were influenced from establishment, employee, and the period of analysis. The number of Coliform group for employee's hands was in the range of 10²-10⁴ CFU only at the first analysis. Total aerial bacteria in working area of mass catering establishments was below 7 CFU/Plate and aerial Staphylococcus sp. was not detected at all except one spot.
The analysis of hazardous heavy metals, such as Pb, Cd and As, was conducted from the porcelain dinnerwares. Total 374 samples of those products in the domestic market were purchased for the study. All the samples were extracted by 4% acetic acid solution, followed by the analysis with AAS(Atomic Absorption Spectroscopy). As a result, Pb and As were detected maximum 8.63 ㎍/ml, 2.58 ㎍/ml, respectively. Cd was found in a sample as 0.10 ㎍/ml.
This study was carried out to changes in chemical and microbiological properties of spring waters in Tongyeoung area. In this paper, ninety spring water samples were collected from 9 station for 11 month to evaluated chemical and bacteriological water quality. Range and mean values of constituents of the samples are as followed; water temperature 5.2-25.8℃, 16.3℃, pH 6.0-7.2, 6.7, total residue 33.6-210 mg/1, 90.6 mg/1, turbidity 0.35-5.48, 1.45NTU, KMnO4 consumed 0.51-4.21 mg/1, 1.39 mgll, chloride ion 6.23-42.5, 16.7 mg/1, phosphate-phosphorus ND-0.04, 0.02 mg/1, nitrite-nitrogen ND-0.02, 0.01 mg/l, nitrate-nitrogen ND-3.56, 1.42 mg/1, ammonia-nitrogen ND-0.20, 0.14 mg/1, dissolved total nitrogen ND-3.78, 1.57 mgll, iron 0.04-0.28, 0.13ppm, zinc 0.03-0.66, 0.20ppm, mangan ND-0.01, allumium 0.14-0.58, 0.39ppm, copper ND-0.01, 0.01, lead ND-0.01, 0.0lppm, Arsenic ND-0.01, 0.0lppm, mercury ND-0.02, chrome not detected, cadmium not detetced respectively. The viable cell counts of the spring waters ranged 5.0760/m1(means 130/m1). Range and mean value of total coliform and fecal coliform MPN's of the spring waters were 0-2,400MPN/100 ml, 73MPN/100 ml and 0-540MPN/ 100 ml, 21MPN/100 ml. Spring water quality was usually poor with viable cell counts exceeding 130 CFU/liter and the coliform counts in spring waters of 73 MPN/liter. Composition of coliform by IMViC reaction was 33.3% E. coli, 15.6% Citrobacter freundii, 35.6% Klebsiella aerogenes and others.
The antioxidant effect and sensory evaluation of various concentration of dried insam on gangjung was investigated for 6 months. The results were as follows: 1. The antioxidant effect of each sample were in the rank order of 0$gt;0.5$gt;1.0$gt;1.5$gt;2.0$gt;2.5% of dried insam at 20℃ by acid and peroxide value but the effect did not increase proportionally with increasing concentration. 2. In 3 months, acid and peroxide values increased slowly showing, but after 3 months, acid and peroxide values increased remarkably. 3. The acid value(AV) and the peroxide value(POV) of dried insam gangjung increased according to storage term but there was no significant difference with the kinds of adding methods of dried insam. 4. Sensory evaluation of preference for flavor, texture, taste and total quality of six samples by multiple paired comparison test indicated that gangjung with 1.5% dried insam in maltose was the best among samples.
This study was performed to investigate the contents of sulfites in 1,063 dried seaweeds in Seoul Chung-Bu market from March in 1999 to August in 2000. Sulfites of the samples were determined by Zn powder reduction method and Monnier-Williams's modified method. Two samples of 1063 (0.19%) were detected over 30ppm in SO₂ contents by Monnier-Williams's modified method. In samples detected over 30ppm, 2 brown algaes were 171.4ppm and 295.7ppm. By Zn powder reduction method, 54 dried seaweeds (54/1063 = 5.08%) were positive reaction (1-30ppm). These were 28 dried layers, 27 dried brown seaweeds and 2 sea cabbages. According to results, the quality test for the dried seaweeds must be reinforced to supply safety food for the citizens.
This study was conducted to determine the content of inorganic metals in soft drinks distributed locally in markets. 6 trace metals (Fe, Ca, Zn, Na, Mg, and K) were detected in 16 kinds of drinks, 80 samples. The average concentration of inorganic metals in vegetable drinks was relatively higher than that of mixed drinks or carbonated drinks. The concentration of calcium, which is advisable inorganic metals for the growth of skeleton and the prevention of osteoporosis, hypertension, was very high and needed to be careful for the consumer who is suffer with lithiasis. Although carbonated drinks are very popular with the children and adolescence owing to the unbalance of the intake of Ca and P, habitual drinking could cause obstruction in skeletal growth and metabolism of Fe, Cu, and Zn. So, it is suggested that more practical study is needed for the intake of inorganic metals.