• Journal of Food Hygiene and Safety
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• v.38 no.1
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• pp.26-30
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• 2023

In this study, we analyzed the microbial contamination level of ultraviolet sterilizer (UVS) chambers and suggested plans to improve hygiene management. In this study, UVS chambers targeted 98 UVS in some childcare centers in Jeollanam-do, Korea. Total aerobic bacteria and coliform bacteria were tested according to the Korean Food Code. Of the 98 UVS chambers, total aerobic bacteria were detected in 67 (68.4%) and coliform bacteria in 5 (5.1%). Six kinds of food-poisoning bacteria, including Salmonella spp., were not detected, but Bacillus cereus was detected in 1 (2.8%) out of 98 UVS chambers. According to the UV lamp replacement period, the detection rate of total aerobic bacteria was 3 (50%) out of 6 UVS within 3 months, 3 (60%) out of 5 UVS in 3 to 6 months, and 61 (70.1%) out of 87 UVS over 6 months. The detection rate of coliform bacteria according to the UV lamp replacement period was not detected within 6 months, however, they were detected in 5 (5.7%) out of 87 chambers after more than 6 months. The level of microbial contamination in the UVS chambers was higher as the lamp replacement period was longer. Considering these results, it was determined that the UVS chambers should be kept dry and clean, and the UV lamp should be replaced periodically. In addition, it is necessary to provide the staff catering for childcare centers with continuous education regarding the cleaning of UVS chambers and the replacement of UV lamps.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.814-818
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• 2011

The seasonal changes were evaluated in the soil microbial populations by selected media in an organic farming system (OFS) with no-till management compared to those in a conventional farming system (CFS) with tillage and synthetic amendments in a flooded paddy from 2009 to 2010. The populations of aerobic bacteria and fungi in the OFS were significantly higher than those in the CFS at the harvesting stages, whereas those of Gram-negative bacteria was significantly higher in the OFS than in the CFS before the submerging stages. In addition, populations of aerobic bacteria, Gram-negative bacteria, and fungi tended to rapidly decreased after the submerging stages may be due to insufficient oxygen. Gram-negative bacteria should be considered as potential factor responsible for the microbial population differentiation observed between the OFS and the CFS in flooded paddy fields.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.3
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• pp.421-429
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• 2019

Objective: In this study, the effects of vacuum (VP) and high-oxygen modified atmosphere ($80%\;O_2+20%\;CO_2$) packaging (HiOx-MAP) on physico-chemical and microbiological properties of minced water buffalo meat were investigated. Methods: After minced meat preparation, samples were packaged under VP and HiOx-MAP and stored at $2^{\circ}C{\pm}0.5^{\circ}C$ for 14 days. Samples taken on certain days were subjected to total aerobic mesophilic bacteria, total aerobic psychrotrophic bacteria, lactic acid bacteria, Pseudomonas, Enterobacteriaceae and yeast-mold counts as well as pH, color ($L^*$, $a^*$, and $b^*$) and thiobarbituric acid reactive substances (TBARS) analyses. Results: In minced water buffalo meat packaged under HiOx-MAP, TBARS value exceeded 1 mg malondialdehyde/kg on the 4th day of the storage. In VP samples, TBARS value remained close to initial TBARS value during storage. According to the findings, $a^*$ value was determined to be high in the HiOx-MAP samples within initial days of the storage. However, no significant changes in $a^*$ value were observed in VP samples during storage. In contrast, the mean value of $L^*$ was detected as higher in HiOx-MAP sample than VP samples. The count of psychrotrophic bacteria increased more than that of mesophilic bacteria during storage. The growth of Enterobacteriaceae and Pseudomonas was delayed in both the packaging methods. However, lactic acid bacteria exhibited more growth in VP samples compared to MAP samples. Conclusion: The lipid oxidation proceeded faster than expected in minced water buffalo meat packed with HiOx-MAP method. This situation adversely affected the $a^*$ value. On the other hand, similar microbiological results were obtained in both packing methods.

• Environmental Engineering Research
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• v.13 no.2
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• pp.51-65
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• 2008

The increasing demand for energy in the near future has created strong motivation for environmentally clean alternative energy resources. Microbial fuel cells (MFCs) have opened up new ways of utilizing renewable energy sources. MFCs are devices that convert the chemical energy in the organic compounds to electrical energy through microbial catalysis at the anode under anaerobic conditions, and the reduction of a terminal electron acceptor, most preferentially oxygen, at the cathode. Due to the rapid advances in MFC-based technology over the last decade, the currently achievable MFC power production has increased by several orders of magnitude, and niche applications have been extended into a variety of areas. Newly emerging concepts with alternative materials for electrodes and catalysts as well as innovative designs have made MFCs promising technologies. Aerobic bacteria can also be used as cathode catalysts. This is an encouraging finding because not only biofouling on the cathode is unavoidable in the prolonged-run MFCs but also noble catalysts can be substituted with aerobic bacteria. This article discusses some of the recent advances in MFCs with an emphasis on the performance, materials, microbial community structures and applications beyond electricity generation.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.392-397
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• 1996

To produce low salt fermented anchovy by an accelerated method with Asp. oryzae and Bacillus sp. koji, enzyme activity and variation of microflora during the 60 day fermentation were examined. Bacterial counts changed a little during the fermentation with the highest on day 40 for proteolytic and anaerobic bacteria and on day 20 for aerobic bacteria. Proteolytic, lipolytic, aerobic, and anaerobic bacteria counts were higher in the Bacillus sp. koji added anchovy paste than in others. The protease and lipase activities reached the highest point on day 20 and 30, respectively, and decreased gradually afterwards. The protease activity was higher in Asp. oryzae koji than in bacillus sp. koji, but the lipase activity was to the contrary.

• The Korean Journal of Malacology
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• v.24 no.1
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• pp.25-32
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• 2008

In order to estimate the necessity of refrigerated storage of fresh seafood for short-term storage, and evaluate the effect of refrigerated storage on pen shell Atrina pectinata and clam Ruditapes philippinarum collected from Jang-su of Deukryang Bay and I-mok of Sunchen Bay in South Korea, the counts of coliform, Escherichia coli and total aerobic bacteria in A. pectinata and R. philippinarum under non-refrigerated $(28{\pm}1^{\circ}C)$ and refrigerated storage conditions $(4{\pm}1^{\circ}C)$ were determined. The results indicated that the storage at temperature of $4^{\circ}C$ possessed significant effects on inhibiting bacterial growth in live seafood. And refrigerated storage had different effect on A. pectinata and R. philippinarum. Different species and culture environments significantly influenced the initial and ultima bacteria counts. This study confirmed that refrigerated storage for short-term storage of live seafood was necessary, and indicated that the effect of refrigerated storage was influenced by comprehensive effectors.

• Korean Journal of Veterinary Service
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• v.40 no.4
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• pp.245-251
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• 2017

Cold air or ice water are used to chill poultry carcasses after slaughter. In order to compare the microbial reduction effect of two different chilling systems in poultry carcasses, Pre-and post-chilled carcass samples were tested for contamination agents such as aerobic bacteria counts, E. coli counts and Salmonella spp. counts. Water chilling system showed higher reduction ratio of bacteria than air chilling system during the three seasons. Also, aging of slaughter facility was related with bacterial contamination of pre-chilld carcasses. And additional volatile basic nitrogen (VBN) test were conducted in poultry packing meats and it increased steadily during 15 days. VBN at 8~9 days were over 13 mg% with putrid smell. Poultry packing meats by water chilling system were fresher than air chilling system during early storage time. But those decayed faster after 9 days.

• Journal of Preventive Medicine and Public Health
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• v.10 no.1
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• pp.134-137
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• 1977

The most efficient method for reducing the organic content of dilute liquid waste is by aerobic-biological treatment. Basically, the organisms responsible for treatment possess the ability to decompose complex organic compounds and to use the energy so liberated for their bodily functions: reproduction, growth, locomotion and so on. That part of organic matter used to produce energy is converted to the essentially stable end products of carbon dioxide, water and ammonia, while the remainder is converted to new cells which can be settled and thus removed from the liquid before the waste is discharged to the receiving body water. Oxygen must be supplied continuously during the aerobic process. In the field of sewage treatment the Warburg respirometer is used mainly for the measurement of the oxygen uptake of samples. In this experiment the Warburg constant volume respirometer was used to determine the oxygen uptake by bacteria in the presence of various glucose concentrations. The rate of oxygen uptake by the bacteria was expressed as the respiratory quotient. The result indicated that the oxygen uptake was proportional to the glucose concentration. The expecting equation of the regression line was Y=7.7+0.12X where Y: respiratory quotient, ${\mu}l.\;O_2$ taken up/mg. dry wt. bacterium/hr. X: concentration of glucose, mg/l

• The Korean Journal of Food And Nutrition
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• v.13 no.6
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• pp.558-562
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• 2000

A strain of non-sulfur photosynthetic bacteria possessing large amount of ubiquinone-10 in the cell mass, was isolated from waste water collected from the Nakdong River. It was identified as Rhodobacter sp. N-2 by a series of studies on its morphological. cultural and physiological characteristics. The organism appeared to got higher cell mass under circumstances of anaerobic growth conditions than under photosynthetic aerobic cultures. Biotin and thiamin and niacin could be used as good growth factors.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.7
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• pp.988-995
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• 2019

Objective: This study was conducted to estimate the temperature and microbial changes of corn silages during aerobic exposure. Methods: Kwangpyeongok (KW) and Pioneer 1543 (PI) corn hybrids were harvested at 29.7% of dry matter and chopped to 3 to 5 cm lengths. Homo (Lactobacillus plantarum; LP) or hetero (Lactobacillus buchneri; LB) fermentative inoculants at $1.2{\times}10^5$ colony forming unit/g of fresh forage was applied to the chopped corn forage which was then ensiled in quadruplicate with a $2{\times}2$ (hybrid${\times}$inoculant) treatment arrangement for 100 days. After the silo was opened, silage was sub-sampled for analysis of chemical compositions, in vitro digestibility, and fermentation indices. The fresh silage was continued to determine aerobic exposure qualities by recorded temperature and microbial changes. Results: The KW silages had higher (p<0.01) in vitro digestibilities of dry matter and neutral detergent fiber than those of PI silages. Silages applied with LB had higher (p<0.001) acetate concentration, but lower (p<0.01) lactate concentration and lactate to acetate ratio than those of LP silages. The interaction effect among hybrid and inoculant was detected in acetate production (p = 0.008), aerobic stability (p = 0.006), and lactic acid bacteria count (p = 0.048). The yeast was lower (p = 0.018) in LB silages than that in LP silages. During the aerobic exposure, PI silages showed higher (p<0.05) temperature and mold than KW silages, while LP silages had higher (p<0.05) lactic acid bacteria and yeast than LB silages. Conclusion: The results indicated that the changes of silage temperature during aerobic exposure seems mainly affected by mold growth, while applied LB only enhanced aerobic stability of PI silages.