• Food Science and Biotechnology
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• 제15권5호
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• pp.715-720
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• 2006

This study was performed to develop a predictive model for the growth kinetics of Listeria monocytogenes in tryptic soy broth (TSB) using a response surface model with a combination of potassium lactate (PL), temperature, and pH. The growth parameters, specific growth rate (SGR), and lag time (LT) were obtained by fitting the data into the Gompertz equation and showed high fitness with a correlation coefficient of $R^2{\geq}0.9192$. The polynomial model was identified as an appropriate secondary model for SGR and LT based on the coefficient of determination for the developed model ($R^2\;=\;0.97$ for SGR and $R^2\;=\;0.86$ for LT). The induced values that were calculated using the developed secondary model indicated that the growth kinetics of L. monocytogenes were dependent on storage temperature, pH, and PL. Finally, the predicted model was validated using statistical indicators, such as coefficient of determination, mean square error, bias factor, and accuracy factor. Validation of the model demonstrates that the overall prediction agreed well with the observed data. However, the model developed for SGR showed better predictive ability than the model developed for LT, which can be seen from its statistical validation indices, with the exception of the bias factor ($B_f$ was 0.6 for SGR and 0.97 for LT).

• Food Science and Biotechnology
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• 제14권6호
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• pp.847-853
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• 2005

A total of 60 growth curves were generated with combinations of temperature, pH, and potassium lactate (PL) (60% (v/v) commercial solution) to determine the lag time (LT) and specific growth rate (SGR) of L. monocytogenes in broth. LT and SGR were significantly (P<0.05) affected by temperature, pH, concentration of PL, or the combined interaction of these factors. LT was extended and SGR was reduced significantly (P<0.05) by increased concentration of PL at lower temperature and pH. Listericidal effect was observed in the broth containing 2, 3, and 4% PL at pH 5.0 and $4^{\circ}C$. The antimicrobial activity of PL against L. monocytogenes increased when the pH of the medium was decreased at all temperatures tested. The results suggest that PL has antimicrobial properties to suppress the growth of L. monocytogenes. Potassium lactate has many potential applications as an antimicrobial additive in variety of refrigerated ready-to-eat foods.

• Fisheries and Aquatic Sciences
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• 제26권10호
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• pp.583-592
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• 2023

Celebes rainbow (Marosantherina ladigesi) is one of Indonesia's exported ornamental fish commodities, but the exploitation of this fish only relies on wild catches. The rise of unlimited fishing, especially those using poison, has changed the aquatic environment, threatening sustainability and causing fish extinction. This study aimed to evaluate the effectiveness of several types of feed in improving the absolute growth rate (AGR), specific growth rate (SGR), survival rate (SR), feed conversion ratio (FCR), feed efficiency (FE), hematology, and immune response of Celebes rainbow. The fish used in this study were male ornamental Celebes rainbow (M. ladigesi) weighing 1.32 ± 0.21 g/ind, reared in 54 L-aquariums at a stocking density of 30 individuals/aquarium for six weeks. The fish were fed according to the test diet consisting of live Tubifex sp worms, dry Tubifex sp worms, Spirulina platensis, and crumble pellets. The parameters observed were AGR, SGR, SR, FCR, FE, hematology, intestinal histology, liver histology, and a challenge test with the pathogenic bacteria Aeromonas hydrophila. The results showed that fish-fed live Tubifex sp worms had better AGR, SGR, SR, FCR, FE, hematology, and disease resistance compared to all other treatments. These results indicate that live Tubifex sp worms are the best feed for rearing Celebes rainbow.

• 한국양식학회지
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• 제21권1호
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• pp.47-53
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• 2008

본 연구의 목적은 rotifer Brachionus rotundiformis의 영양강화와 자어의 소화기능을 높이기 위해 소화효소 활성이 높은 rotifer의 선택방법을 제시하는 것이다. 소화효소 활성을 측정하는 개체군은 성장과정에 있는 개체군들 중 임의로 표본 수집하여 소화효소활성을 측정하여 결정하였다. 선택된 개체군에서 개체밀도와 성장률의 관계가 RD=5865 SGR-350.08(P<0.001)로 나타났다. 포란률은 성장률과 개체밀도와의 관계가 각각 F=-36.147 SGR+61.652(P<0.05)와 F=-0.0085 RD+66.38(P<0.001)로 나타났다. 성장률과 소화효소 활성의 rotifer 개체당 활성은 Amyl=-1.6482 SGR+3.2498(P<0.05), TAP=-0.8115 SGR+1.1361(P<0.001) 및 TGL+0.0055 SGR+0.0079(P=0.239)로 나타나 TG-lipase 활성에서는 성장률과 관계없는 것으로 나타났다. 또한 포란률과 rotifer 개체당 소화효소 활성의 관계는 Amyl=0.0296 F+1.0981(P<0.001). TAP=0.0252 F+0.0975(P<0.001) 및 TGL=-6E-06 F+0.0113(P=0.915)으로 나타나 TG-lipase 활성이 포란률과 관계없는 것으로 나타났다. 반면 TG-lipase의 단백질 비활성과 포란률, 성장률 및 개체밀도와의 관계는 각각 TGL=-0.0024 F0.2332(P=0.132), TGL=0.1267 SGR+0.005(P<0.01) 및 TGL=0.0002 F-0.0594(P<0.001)로 나타나 TG-lipase 단백질 비활성은 포란률과의 관계를 제외하고 각각 상관된 변화를 보였다. 따라서 rotifer의 영양강화효과와 자어에게 외부기인 소화효소 전달을 위한 높은 소화효소 활성을 보이는 rotifer 개체군이 개체밀도가 높은 개체군보다는 포란률이 높은 경우에 나타났기 때문에 포란률이 높은 개체군을 선택하여 영양강화하고 자어에 공급하는 것이 보다 자어에 유익할 것으로 판단된다.

• 동아시아식생활학회지
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• 제22권4호
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• pp.558-565
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• 2012

The objective of this study was to develop a predictive growth model for Bacillus cereus in nutrient broth and validate the developed growth model in blanched vegetables. After inoculating B. cereus into nutrient broth, growth of B. cereus was investigated at 13, 17, 24, 30 and $35^{\circ}C$. Lag time (LT) decreased while specific growth rate (SGR) increased with an increase in storage temperature. Growth of B. cereus was not observed at temperatures lower than $12^{\circ}C$. Secondary growth models were developed to describe primary model parameters, including LT and SGR. Model performance was evaluated based on bias factor ($B_f$) and accuracy factor ($A_f$). In addition, we inoculated B. cereus into blanched vegetables stored at 13, 24, $35^{\circ}C$ and observed the growth kinetics of B. cereus in five different blanched vegetables. Growth of B. cereus was most delayed on Doraji at $13^{\circ}C$ and was not observed on Gosari at $13^{\circ}C$. Growth of B. cereus at $35^{\circ}C$ was significantly (p<0.05) slower on Gosari than on other blanched vegetables. The developed secondary LT model for broth in this study was suitable to predict growth of B. cereus on Doraji and Gosari, whereas the SGR model was only suitable for predicting the growth of B. cereus on mung bean sprout.

• Food Science and Biotechnology
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• 제16권2호
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• pp.238-242
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• 2007

Square root models were developed for predicting the kinetics of growth of Listeria monocytogenes in sesame leaves as a function of temperature (4, 10, or $25^{\circ}C$). At these storage temperatures, the primary growth curves fit well ($R^2=0.898$ to 0.980) to a Gompertz equation to obtain lag time (LT) and specific growth rate (SGR). The square root models for natural logarithm transformations of the LT and SGR as a function of temperature were obtained by SAS's regression analysis. As storage temperature ($4-25^{\circ}C$) decreased, LT increased and SGR decreased, respectively. Square root models were identified as appropriate secondary models for LT and SGR on the basis of most statistical indices such as coefficient determination ($R^2=0.961$ for LT, 0.988 for SGR), mean square error (MSE=0.l97 for LT, 0.005 for SGR), and accuracy factor ($A_f=1.356$ for LT, 1.251 for SGR) although the model for LT was partially not appropriate as a secondary model due to the high value of bias factor ($B_f=1.572$). In general, our secondary model supported predictions of the effects of temperature on both LT and SGR for L. monocytogenes in sesame leaves.

• Environmental Analysis Health and Toxicology
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• 제23권2호
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• pp.101-112
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• 2008

Effects of various concentrations of copper on growth change of blue-greenalgae Anabaena flos-aquae were studied. There was significant differences among cultures treated with various concentrations of copper in growth of algae with parameters of cell numbers, specific growth rate (SGR) and chlorophyll contents. Algal growth and SGR were inhibited on by effect of various concentrations of copper more than without copper (ANOVA, F=34.69 p<0.001, F=114.89, p<0.001). The SGRs of various concentrations of copper in media were higher than without copper on 8 days after copper treated. The mean of chlorophyll contents was 1.978 ${\mu}g{\cdot}mL^{-1}$ and 1.648 ${\mu}g{\cdot}mL^{-1}$, respectively, while those of algae in culture without copper was 3.179 ${\mu}g{\cdot}mL^{-1}$ (ANOVA, F=153.74, p<0.001). The cellular morphology was different between media of which copper treated and without copper. The colony of algae in media which copper treated was shorter than without copper. Effects of various concentrations of copper on growth change of blue-green-algae Anabaena flos-aquae occured variety changes of parameters of cell numbers, specific growth rate (SGR), chlorophyll contents and cellular morphology on growth of algae.

• 한국식품위생안전성학회지
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• 제28권2호
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• pp.168-173
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• 2013

본 연구는 신선편이 식품에서 오염 가능성이 있는 병원성 식중독 균 E. coli O157:H7에 대해 파프리카에서 성장 예측 모델을 적용하고, 본 연구에서 개발된 성장 예측 모델을 내부 검증하였다. 이를 비교하여 신선편이 식품을 안전하게 관리하기 위한 적절한 모델을 제시하고자 하였다. 파프리카에 E. coli O157:H7접종하여 온도에 따라 12, 24, 30, $36^{\circ}C$에 보관하여 성장을 측정하였다. Gompertz 식을 이용하여 온도에 따른 성장곡선을 그리고 LT와 SGR을 산출하였다. 산출된 LT와 SGR은 각각 Davey model와 squareroot model를 이용하여 2차 모델을 개발하였다. 개발된 2차 모델에 대하여 LT와 SGR model의 $R^2$값은 각각 0.999, 0.994로 1에 근접하는 높은 적합성을 보였다. 또한 내부 검정 결과 LT와 SGR model의 Bf 값은 각각 1.01, 0.89, LT model은 안전하게 SGR model 위험하게 예측되었다. 파프리카의 LT와 SGR의 상대적인 오차 값은 모두 허용 가능한 오차 범위에 포함 되었다. 따라서 개발된 모델을 이용하여 온도에 따른 E. coli O157:H7성장을 추정할 수 있으며, 이를 위해평가 자료로 활용할 수 있을 것으로 보인다.

• Fisheries and Aquatic Sciences
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• 제15권4호
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• pp.305-311
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• 2012

We investigated compensatory growth of Nile Tilapia Oreochromis niloticus in structural size and live weight in response to different deprivation periods and refeeding. Four treatments were assigned randomly to fish in 12 glass tanks, with each treatment performed in triplicate. The control group was fed to satiation three times a day throughout the experiment. The other three treatment groups were starved for 1 week (S1), 2 weeks (S2), or 4 weeks (S4) and then fed until the end of the experiment. After the experiment, no significant differences were observed among S1, S2, and the control group in average weight or length, whereas the weight and length of S4 were significantly reduced. Relative condition factors of the three starved groups decreased significantly until the end of the restricted period but recovered rapidly after refeeding. The specific growth rate in weight ($SGR_W$) of the three restricted groups recovered quickly upon refeeding and were significantly higher than the control group, but these differences disappeared gradually until the end of the experiment. No significant difference in specific growth rate in length ($SGR_L$) was noted between the control group and the three restricted groups after refeeding. All three groups showed hyperphagia for a short period upon refeeding, and no statistical differences were observed in feeding efficiency among the four groups.

• 한국패류학회지
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• 제30권3호
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• pp.227-234
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• 2014

본 연구는 해상가두리의 먹이공급비율에 따른 성장 및 생존율을 조사하고, 실내육상양식의 먹이 공급율과의 비교를 통해 국내 주요 북방전복 양성방법인 해상가두리와 함께 실내 사육 수조의 적정 천연먹이의 공급율을 제안하여 북방전복 생산성 향상을 유도하고자 실시하였다. 먹이공급율은 전복 어체중량을 기준으로 일간공급율 (daily feeding rate, DFR) 5, 10, 15, 20% (5DFR, 10DFR, 15DFR, 20DFR) 를 설정하여, 해상가두리와 실내육상수조에서 2반복으로 13개월간 실시하였다. 해상가두리에서 사육한 전복 (최초 수용 시 평균각장 $54.18{\pm}7.39mm$) 성장에서 각 장과 각폭의 절대성장율 (absolute growth rate, ARG), 일간 성장율 (daily growth rate, DGR) 및 특수생장율 (specific growth rate, SGR) 과 중량의 증중률 (weight gain, WG), 일간증중률 (daily weight gain, DWG) 및 특수증중률(specific weight gain, SWG), 그리고 생존율에서 20DFR이 유의적으로 낮았다 (P < 0.05). 실내육상수조에서 사육한 전복 (최초 수용 시 평균각장 $49.70{\pm}2.28mm$) 의 각장, 각폭의 ARG, DGR, SGR과 중량의 WG, DWG, SWG에서는 5DFR, 10DFR이 유의적으로 높았고 (P < 0.05), 생존율은 20DFR이 유의적으로 낮았다 (P < 0.05). 따라서 해상가두리와 실내육상수조 전복양식 자연먹이의 일간 공급율은 성장과 생존율, 그리고 경제적 측면까지 고려하면 어체중량의 5-10%에서 공급해야 한다.