• 한국환경보건학회지
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• 제33권2호
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• pp.145-149
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• 2007

The range of reduction rates of airborne bacteria concentration at 6 hrs, 12 hrs, 24 hrs and 48 hrs, which means a storage time until input of agar media into incubator after air sampling with an impactor. were 15-20%, 25-40%, 35-50% and 55-70%, respectively, compared to initial concentration. Types of agar media and storage thermal condition did not significantly affect a collection efficiency of impactor in terms of evaluating airborne bacteria level (p>0.05). To better improve the impactor's collection efficiency of airborne bacteria, based on the result of this study, it is recommended that the vicinity of $25^{\circ}C$ should be sustained until input of agar media into incubator after air sampling.

• 한국식품영양과학회지
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• 제28권5호
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• pp.1069-1075
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• 1999

The sterilization was attempted to improve the quality deterioration of soybean paste during its storage. For this experiment, soybean paste was sterilized at 80oC for 30 minutes and stored during 6 months at 15oC and 30oC, respectively. The total approximate composition contents were moisture 52.5%, crude protein 11.94%, crude fat 2.0%, amino nitrogen 413.3mg%, sodium chloride 11.61% and ash 15.5%. According to the increase of storage period, pH was decreased gradually because of the increase of organic acids by the metabolism of microorganisms and the acid accumulation by acid forming bacteria, but titratable acidity was increased during storage. Amino nitrogen was rapidly increased for the first one or two month storage period and maintained as the same level for the rest of them. Each amino acid contents of soybean paste, which were glutamic acid, tryptophan, proline, arginine, and aspartic acid, had much higher level than others. In color changes sterilized soybean paste(SSP) was much lower than that of raw ones(RSP). Hunter L and b values on the surface of soybean paste were decreased during storage, and the decreasing levels were higher at 30oC than at 15oC. Hunter a value, however, was increased a little in the initial storage, and thereafter it was decreased. Lactic acid bacteria, yeasts, and molds were disappeared completely by the sterilization. However, the bacteria of aerobes and anaerobes were not disappeared by this processing.

• 한국식생활문화학회지
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• 제39권3호
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• pp.147-155
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• 2024

This study analyzed the changes in the nutritional components, properties, physicochemical properties, general bacteria, and lactic acid bacteria of pickled cabbage depending on the cultivation area. An analysis of the nutritional composition on the first day of storage showed no significant difference in the calories, carbohydrates, protein, fat, and dietary fiber contents regardless of the cultivation region, but regional differences were observed in the vitamin C content in the order of Andong > Pyeongchang > Haenam. The total free amino acid content appeared in the order Andong > Pyeongchang > Haenam, and the GABA (γ-amino-n-butyric acid) content appeared in the order Haenam > Andong > Pyeongchang. In addition, pickled cabbage was observed on the 1^st, 5^th, and 10^th days of storage at 4℃. No significant change in appearance was observed on the 1^st and 5^th days, but changes were observed on the 10^th day. Regardless of the cultivation area, the salinity (p<0.05) and pH (p<0.05) decreased significantly as the storage period increased, while the sugar content (p<0.05) and acidity (p<0.05) increased significantly. The general bacteria (p<0.05) and lactic acid bacteria (p<0.05) counts increased significantly as the storage period increased, irrespective of the cultivation region.

• 한국축산식품학회지
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• 제29권3호
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• pp.289-295
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• 2009

The aim of this research was to develop predictive models for the growth of spoilage bacteria (total viable cells, Pseudomonas spp., and lactic acid bacteria) on frankfurters and to estimate the shelf-life of frankfurters under aerobic conditions at various storage temperatures (5, 15, and $25^{\circ}C$). The primary models were determined using the Baranyi model equation. The secondary models for maximum specific growth rate and lag time as functions of temperature were developed by the polynomial model equation. During 21 d of storage under various temperature conditions, lactic acid bacteria showed the longest lag time and the slowest growth rate among spoilage bacteria. The growth patterns of total viable cells and Pseudomonas spp. were similar each other. These data suggest that Pseudomonas spp. might be the dominant spoilage bacteria on frankfurters. As storage temperature increased, the growth rate of spoilage bacteria also increased and the lag time decreased. Furthermore, the shelf-life of frankfurters decreased from 7.0 to 4.3 and 1.9 (d) under increased temperature conditions. These results indicate that the most significant factor for spoilage bacteria growth is storage temperature. The values of $B_f$, $A_f$, RMSE, and $R^2$ indicate that these models were reliable for identifying the point of microbiological hazard for spoilage bacteria in frankfurters.

• Asian-Australasian Journal of Animal Sciences
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• 제32권3호
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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.

• Journal of Microbiology and Biotechnology
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• 제32권12호
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• pp.1599-1604
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• 2022

Storage stability of freeze-dried lactic acid bacteria is a critical factor for their cost-effectiveness. Long-term storage of lactic acid bacteria enables microbial industry to reduce distribution costs. Herein, we investigated the effect of cold adaptation under supercooling conditions at -5℃ on the viability of Leuconostoc mesenteroides WiKim32 during the freeze-drying process and subsequent storage. Cold adaptation increased the thickness of exopolysaccharides (EPS) and improved the viability of freeze-dried Leu. mesenteroides WiKim32. Compared to non-adapted cells, cold-adapted cells showed a 35.4% increase in EPS thickness under supercooling conditions. The viability of EPS-hydrolyzed cells was lower than that of untreated cells, implying that EPS plays a role in protection during the freeze-drying process. Cold adaptation increased the storage stability of freeze-dried Leu. mesenteroides WiKim32. Fifty-six days after storage, the highest viability (71.3%) was achieved with cold adaptation at -5℃. When EPS-containing broth was added prior to the freeze-drying process, the viability further increased to 82.7%. These results imply that cold adaptation by supercooling pretreatment would be a good strategy for the long-term storage of Leu. mesenteroides WiKim32.

• The Plant Pathology Journal
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• 제24권1호
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• pp.74-79
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• 2008

This research was conducted to evaluate fungal and bacterial populations in unhulled and brown rice under indoor storage conditions, and to examine the relationship between microbial populations and environmental conditions such as temperature and relative humidity. The temperature and relative humidity of the storage room ranged from $22.6^{\circ}C\;to\;27.0^{\circ}C$ and 23.3% to 44.2%, respectively. Total fungal and bacterial populations remained relatively stable over the storage period. Predominant fungi included Aspergillus candidus, A. flavus, A. fumigatus, and Penicillium spp.; the predominant bacteria were Bacillus, Microbacterium, Sphingomonas, and Methylobacterium spp. Total fungi and bacteria were not significantly correlated with either unhulled (r=0.448, P=0.372) or brown (r=0.466, P=0.351) rice. In unhulled rice, total fungi showed positive correlations with total Aspergillus (r=0.994, P<0.001) and total Penicillium (r=0.906, P<0.05); A. flavus was positively correlated with total Aspergillus (r=0.913, P<0.05) and total fungi (r=0.868, P<0.05). In brown rice, Bacillus spp. was also positively correlated with total bacteria (r=0.998, P<0.001). Mean temperature was negatively correlated with A. candidus (r=-0.852, P<0.05) and total fungi (r=-0.961, P<0.01), and mean relative humidity was positively correlated with total Penicillium spp.(r=0.884, P<0.05) in brown rice. Hence these results could provide basic information on the fungal and bacterial populations in unhulled and brown rice stored under room conditions, and on the effect of environmental conditions on the populations of fungi and bacteria, especially Aspergillus and Penicillium spp.

• 한국식품과학회지
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• 제24권5호
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• pp.470-476
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• 1992

본 연구에서는 우유에 탈지분유 또는 저장기간이 다른 3종의 통일벼(86년산, 88년산, 89년산)를 각각 2%(w/v) 첨가하고 젖산균(Lactobacillus 4종, Leuconostoc 1종)으로 발효하여 커드상의 요구르트를 만든 후, 저장기간이 다른 쌀의 첨가가 젖산균의 산생성과 커드상 요구르트의 품질(관능성, 점도, 저장성)에 미치는 영향을 조사하였다. 쌀의 첨가로 젖산균의 산생성이 대조군(우유로만 만든 요구르트)보다 촉진되었는데, 젖산균의 종(種)에 따라 다소 차이는 있으나 쌀에 의한 젖산균의 산생성 촉진효과는 쌀의 저장기간에 의하여 현저한 영향을 받지 않았다. 관능검사의 결과를 보면 우유에 첨가된 쌀은 저장기간이 다르더라도 요구르트의 관능성에 현저한 영향을 미치지 않았다. 점도 측정의 결과를 보면 쌀의 저장기간이 경과할수록 쌀 첨가 요구르트의 점도가 증가하였으며, 커드상 요구르트는 thixotropic flow의 특성을 나타냈다. $5^{\circ}C$에서 15일간 보존된 쌀 첨가 요구르트의 저장성은 첨가된 쌀의 저장기간에 관계없이 우수하였다.

• Food Science and Biotechnology
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• 제17권3호
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• pp.540-546
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• 2008

Sous vide and packaged cook-chilled soybean sprouts were evaluated for physicochemical quality changes and microbial safety during storage for the purposes of shelf-life extension and industrial application. The physicochemical changes assessed were color, texture, and ascorbic acid concentration. The quality of soybean sprouts became worse with increased periods of storage and better in storage temperature of $3^{\circ}C$ more than in $10^{\circ}C$. The concentration of aerobic bacteria decreased from $2.1{\times}10^8$ to $6.0{\times}10^2\;CFU/g$ after pasteurization, but increased during storage. These bacteria are the same shape as anaerobic and hsychrophilic bacteria, but none of these other organisms were detected after heat treatment. The physicochemical qualities of soybean sprouts and microbial safety were better for products stored at $3^{\circ}C$ than at $10^{\circ}C$. In the case of short storage periods, heat treatment at $70^{\circ}C$ for 2 min was most effective for quality and microbial safety.

• Asian-Australasian Journal of Animal Sciences
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• 제23권7호
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• pp.960-964
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• 2010

Water-cooked salted ducks were tray-packaged and stored under refrigeration ($4{\pm}1^{\circ}C$) in order to evaluate the quality changes during storage. pH, total volatile basic nitrogen (TVB-N), sensory and microbiological analysis were determined at 0, 2, 4, 6, 8, 9 and 10 days of storage. pH value and TVB-N (mg N/100 g) varied from $6.47{\pm}0.16$ to $6.69{\pm}0.10$ and from $5.90{\pm}0.93$ to $13.42{\pm}2.46$, respectively. Sensory results indicated that ducks were unacceptable at the 10th day of storage. The predominant spoilage bacteria at the end of the shelf-life were Brochothrix thermosphacta, lactic acid bacteria (LAB) and minor components were Enterobacteriaceae, members of Micrococci, yeasts and moulds. Pseudomonads were also detected. Both total bacteria and the various spoilage ones, overall, increased from the initial sampling to the final day.