The purpose of this study is to assess the effects of outlook project for olive flounder, from the view point of price stabilization, market efficiency, and causality of the prices in different distribution channels. Analytical results show that the volatility of producer price of olive flounder has been significantly mitigated after the implementation of the outlook project. The market efficiency is estimated to be improved after implementing the outlook project although there is an inefficiency on price determination process in some producing regions. The causality test on the producer and wholesale price shows that producing stage leads the wholesale stage in forming the prices. It is found that Jeju leads the flounder price on the size of 500g and 2kg, while Wando leads the price of 1kg size. These estimation result as whole indicate that outlook project for olive flounder has accomplished the intended goals.
Garlic (Allium sativum) is known to have antimicrobial effects but there are few data on its effects against fish pathogenic bacteria. This study was conducted for possible development of natural food antimicrobials from garlic extracts, particularly allicin. The filter sterilized, aqueous extract of garlic was tested for its ability to inhibit the growth of 7 fish pathogenic bacteria (E. tarda, V. ichthyoenteri, V. harveyi, P. damselae, S. iniae, S. parauberis, L. garviae) using the disc diffusion test, minimum inhibitory concentration test, and minimum bacteriocidal concentration test. The garlic extract inhibited growth and killed most of the organisms tested. The disc diffusion test was performed using garlic extracts (100%, 50%, 25%, 10%, each 20㎍), and MIC test was also performed using a diluted concentration of garlic extracts (488 - 250,000 ㎍/㎖). According to the results, garlic extracts exhibited antimicrobial activity against all of seven bacteria, and these results suggest that this garlic extract can be used as an antimicrobial substance against fish bacterial diseases in the fish industry.
Antibiotic Detection Kit (Combination I), a lateral flow immunoassay (LFIA) developed for detecting antibiotic residues in milk, was utilized for the analysis of antibiotic residues in the muscle tissue of olive flounder. After 5-h treatment of samples by placing them in water dosed with sulfadimethoxine (SDM; 200 g/ton water), the residue depletion of SDM was investigated in 25 cultured olive flounders (Paralichthys olivaceus). Muscles from fish were sampled before treatment and on the 1st, 2nd, 3rd, 4th and 5th days after treatment. The concentration of SDM in the muscle was then determined by LFIA. The absorbance ratio of the sample to the control blank (Bs/Bo) was employed as an index to determine the residue in olive flounder muscle. To investigate the recovery rate, standard solutions were added to muscle samples to obtain final concentrations of 25 and 50 ng/mL in the muscle. The recovery rates of all spiked samples were >96.6% of the spiked value. SDM was detectable in the muscle of fish treated with the drug until the 1st day of the withdrawal period. The present study shows that the LFIA can be easily adopted to detect SDM residues in the tissue of farmed fish.