• Journal of Food Hygiene and Safety
• /
• v.26 no.4
• /
• pp.424-434
• /
• 2011

The increase in the consumption of herb medicines have made their use a public health problem due to the potential fungal contamination and the risk of the presence of my cot ox ins. 360 samples of herb medicines were evaluated for the aflatoxin contamination. The natural occurrence of aflatoxins in these samples were determined using immunoaffinity column clean up and high performance liquid chromatography (HPLC) with post-column derivatization. For samples analyzed, mean levels (incidence) of AFB1, AFB2, AFG1 and AFG2 in positive samples were $1.4\;{\mu}g/kg$(46.4%), $0.4\;{\mu}g/kg$(25.4%), $1.1\;{\mu}g/kg$(37.8%) and $0.9\;{\mu}g/kg$(24.3%), respectively. Recoveries of the full analytical procedure were 71.7~99.7% for AFB1, 88.1~99.2% for AFB2, 82.8~95.5% for AFG1 and 77.9~90.0% for AFG2. The excess cancer risk estimated using the cancer potency of aflatoxin B1 (7 $(mg/kg/day)^{-1}$ for $HBsAg^-$ and 230 $(mg/kg/day)^{-1}$ for $HBsAg^+$) were $1.30{\times}10^{-5}{\sim}1.22{\times}10^{-7}$ for hepatits B surface antigen negative ($HBsAg^-$) and $3.31{\times}10^{-4}{\sim}3.12{\times}10^{-6}$ for hepatits B surface antigen positive ($HBsAg^+$) respectively. In conclusion, although the contamination levels of samples used in the study were low, further actions are also required to undertake a program of herbal surveys in order to access mycotoxin contamination overall so that the safety of public will be protected.

• The Korean Journal of Pesticide Science
• /
• v.15 no.3
• /
• pp.254-268
• /
• 2011

Fenoxycarb, pyriproxyfen and methoprene are juvenile hormone mimic insecticide. These insecticides have been widely used for mosquito, fly, scale insects, and Lepidoptera. The purpose of this study was to develop a simultaneous determination procedure of fenoxycarb, pyriproxyfen and methoprene residues in crops using HPLC-UVD/MS. These insecticide residues were extracted with acetone from representative samples of four raw products which comprised brown rice, apple, green pepper, and Chinese cabbage. The extract was diluted with saline water, and then n-hexane/dichloromethane partition was followed to recover these insecticides from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The analytes were quantitated by HPLC-UVD/MS, using a $C_{18}$ column. The crops were fortified with each insecticide at 3 levels per crop. Mean recovery ratios were ranged from 80.0 to 104.3% in four representative agricultural commodities. The coefficients of variation were less than 4.8%. Quantitative limit of fenoxycarb, pyriproxyfen, and methoprene was 0.04 mg/kg in crop samples. A HPLC-UVD/MS with selected-ion monitoring was also provided to confirm the suspected residues. The proposed simultaneous analysis method was reproducible and sensitive enough to determine the residues of fenoxycarb, pyriproxyfen and methoprene in the agricultural commodities.

• Journal of Food Hygiene and Safety
• /
• v.31 no.1
• /
• pp.28-35
• /
• 2016

Species identification of animal tissues in meat products is an important issue to protect the consumer from illegal and/or undesirable adulteration; for economic, religious and health reasons. In this reason, accurate analytical methods are needed for the labeling of meat products with requiring simple and fast procedure. Recently, applications of PCR in food analysis have been increased because of their simplicity, specificity and sensitivity. Therefore, in this study, a multiplex PCR assay was developed for the simultaneous identification of eight species of cow, pig, chicken, duck, goat, sheep, horse and turkey from raw meats. The primers were designed in different regions of mitochondrial 16S RNA after alignment of the available sequences in the GenBank database. Two multiplex primer sets were designed as Set 1 (cow, pig, chicken, duck) and Set 2 (goat, sheep, horse, turkey), respectively. Total 274 samples from cow (n = 55), pig (n = 30), chicken (n=30), and duck (n = 30), goat (n = 40), sheep (n = 33), horse (n = 41), and turkey (n = 15) were tested. The primers generated specific fragments of 94, 192, 279, 477 bp (pig, chicken, cow, duck), 670, 271, 152, 469 bp (goat, sheep, horse, turkey) lengths for eight species, respectively. The animal species specificity was 100% in all eight samples in the multiplex PCR assay. The detection limit of the multiplex PCR assay showed from 100 fg to 1 pg of template DNA from extracted from raw meats. When applying multiplex PCR assays to sample from pork/beef and pork/chicken, beef/chicken tested raw mixed meats and heat-treated ($83^{\circ}C$ for 30min, $100^{\circ}C$ for 20min, and $121^{\circ}C$ for 10min) mixtures, detection limit was 0.1% level beef, pork and pork in beef and chicken in pork and 1.0% level pork in chicken. This study suggest that the developed multiplex PCR assay can be used for rapid and simultaneous species identification of cow, pig, chicken, duck, goat, sheep, horse and turkey from meats.

• Journal of Food Hygiene and Safety
• /
• v.29 no.2
• /
• pp.131-140
• /
• 2014

The objective of this study was to develop a simultaneous method of 8 penicillin antibiotics including amoxicillin, ampicillin, cloxacillin, dicloxacillin, nafcillin, oxacillin, penicillin G and penicillin V in meat using LC-MS/MS. The procedure involves solid phase extraction with HLB cartridge and subsequent analysis by LC-MS/MS. To optimize MS analytical condition of 8 compounds, each parameter was established by multiple reaction monitoring in positive ion mode. The chromatographic separation was achieved on a $C_{18}$ column with a mobile phase of 0.05% formic acid and 0.05% formic acid in acetonitrile at a flow rate of 0.2 mL/min for 20 min with a gradient elution. The developed method was validated for specificity, linearity, accuracy and precision in beef, pork and chicken. The recoveries were 71.0~106%, and relative standard deviations (RSD) were 4.0~11.2%. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.003~0.008 mg/kg and 0.01~0.03 mg/kg, respectively, that are below maximum residue limit (MRL) of the penicillins. This study also performed survey of residual penicillin antibiotics for 193 samples of beef, pork and chicken collected from 9 cities in Korea. Penicillins were not found in all the samples except a sample of pork which contained cloxacillin (concentration of 0.08 mg/kg) below the MRL (0.3 mg/kg).

• Journal of Yeungnam Medical Science
• /
• v.7 no.1
• /
• pp.81-93
• /
• 1990

The author fractographically analyized the cause of metal failure(the first time this procedure has been used for this metal failure)and also analyized it clinically. In this study, I selected eight cases which have been analyized fractographically. In all these cases, the analysis was done after treatment of metal failure of implants internally fixed to femur shaft fractures at the Department of Orthopedic Surgery, Yeung-Nam University Hospital during the six year period from May 1983 to September 1989. 1. Metal failure occured in five dynamic-compression plates, one Jewett nail, one screw in Rowe plate, and one interlocking nail. 2. The clinical cause of metal failure was deficiency of medial butress in five cases, incorrect position of implant in one case, and incorrect selection of implant in two cases. 3. The time interval between internal fixation and metal failure was four months in one case, between five months to twelve months in six cases, three years in one case. 4. The fractographically analytical cause of metal failure was ; first, impact failure, one case, second, fatigue failure, six cases, machining mark(stress liser), four cases type : low consistent cyclic fatigue failure irregular cyclic fatigue failure third, stress corrosion crack, one case. 5. 316L Stainless Steel has good resistance to corrosion. However, when its peculiar surface film is destroyed by fretting, it shows pitting corrosion. This is, perhaps, the main cause of metal failure. 6. It is possible that mechanical injury occured in implants during the manufacturing of implants or that making a screw hole is the main cause of metal failure.

• Journal of Food Hygiene and Safety
• /
• v.37 no.6
• /
• pp.373-384
• /
• 2022

Fluoxastrobin a fungicide developed from Strobilurus species mushroom extracts, can be used as an effective pesticide to control fungal diseases. In this study, we optimized the extraction and purification of fluoxastrobin according to its physical and chemical properties using the QuEChERS method and developed an LC-MS/MS-based analysis method. For extraction, we used acetonitrile as the extraction solvent, along with MgSO₄ and PSA. The limit of quantitation of fluoxastrobin was 0.01 mg/kg. We used 0.01, 0.1, and 0.5 mg/kg of five representative agricultural products and treated them with fluoxastrobin. The coefficients of determination (R²) of fluoxastrobin and fluoxastrobin Z isomer were > 0.998. The average recovery rates of fluoxastrobin (n=5) and fluoxastrobin Z isomer were 75.5-100.3% and 75.0-103.9%, respectively. The relative standard deviations (RSDs) were < 5.5% and < 4.3% for fluoxastrobin and fluoxastrobin Z isomer, respectively. We also performed an interlaboratory validation at Gwangju Regional Food and Drug Administration and compared the recovery rates and RSDs obtained for fluoxastrobin and fluoxastrobin Z isomer at the external lab with our results to validate our analysis method. In the external lab, the average recovery rates and RSDs of fluoxastrobin and fluoxastrobin Z isomer at each concentration were 79.5-100.5% and 78.8-104.7% and < 18.1% and < 10.2%, respectively. In all treatment groups, the concentrations were less than those described by the 'Codex Alimentarius Commission' and the 'Standard procedure for preparing test methods for food, etc.'. Therefore, fluoxastrobin is safe for use as a pesticide.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.18
• /
• pp.88-123
• /
• 1975

To obtain useful fundamental informations for improving cultural practices of barley, an investigation was made on the influences of different fertilizer level and seeding rate as well as seeding date on yield and yield components and their balancing procedure using barley variety Suwon ＃ 18, and at the same time, 8 varieties including Suwon ＃ 18 were also tested to clarify the varietal responses in terms of their yield and yield components under different seeding date at Crop Experiment Station, Suwon, during the period of 1969 and 1970. The results obtained were summarized as follows; 1. Days to emergence of barley variety Suwon ＃ 18 at Suwon, took 8 to 19 days in accordance with given different seeding date (from Sept. 21 to Oct. 31). Earlier emergence was observed by early seeding and most of the seeds were emerged at 15$0^{\circ}C$ cumulated soil temperature at 5cm depth from surface under the favorable condition. 2. Degree of cold injury in different seeding date was seemed to be affected by the growth rate of seedlings and climatic condition during the wintering period. Over growth and number of leaves less than 5 to 6 on the main stem before wintering were brought in severe cold damage during the wintering period. 3. Even though the number of leaves on the main stem were variable from 11 to 16 depending upon the seeding date. this differences were occurred before wintering and less variation was observed after wintering. Particularly, differences of the number of main stem leaves from September 21 to October 11 seeding date were occurred due to the differences of number of main stem leaves before wintering. 4. Dry matter accumulation before wintering was high in early seeded plot and gradually decreased in accordance with delayed seeding date and less different in dry matter weight was observed after wintering. However, the increment rate of this dry matter was high from regrowth to heading time and became low during the ripening period. 5. Number of tillers per $\m^2$ was higher in early seeding than late one and dense planting was higher in the number of tillers than sparse planting. Number of tillers per plant was lower in number and variation in dense planting, and reverse tendency was observed in sparse planting. By increasing seedling rate in early seeding date the number of tiller per plant was remarkably decreased, but the seeding rate didn't affect the individual tillering capacity in the late seeding date. 6. Seedlings were from early planting reached maximum tillering stage earlier than those from the late planting and no remarkable changes was observed due to increased seeding rate. However. increased seeding rate tends to make it earlier the maximum tillering stage early. 7. Stage of maximum tillering was coincided with stage of 4-5 main stem leaves regardless the seeding date. 8. Number of heads per $\m^2$ was increased with increased seeding rate but considerable year variation in number of heads was observed by increased fertilizer level. Therefore, it was clear that there is no difficulties in increasing number of heads per $\m^2$ through increasing both fertilizer level and seeding rate. This type of tendency was more remarkable at optimum seeding time. In the other hand, seeding at optimum time is more important than increasing seeding rate, but increasing seeding rate was more effective in late seeding for obtaining desirable number of heads per $\m^2$. 9. Number of heads per $\m^2$ was decreased generally in all varieties tested in late seeding, but the degree of decrease by late seeding was lower in Suwon ＃ 18. Yuegi, Hangmi and Buheung compared with Suwon ＃ 4, Suwon ＃ 6, Chilbo and Yungwolyukak. 10. Highly significant positive correlations were obtained between number of head and tillers per $\m^2$ from heading date in September 21 seeding, from before-wintering in October 1 seeding and in all growth period from October 11 to October 31 seeding. However, relatively low correlation coefficient was estimated between number of heads and tillers counted around late March to early April in any seeding date. 11. Valid tiller ratio varied from 33% to 76% and highest yield was obtained when valid tiller ratio was about 50%. Therefore, variation of valid tiller ratio was greater due to seeding date differences than due to seeding rate. Early seeding decreased the valid tiller ratio and gradually increased by delaying seeding date but decreased by increasing seeding rate. Among the varieties tested Suwon ＃ 18, Hangmi, Yuegi as well as Buheung should be high valid tiller ratio not only in late seeding but also in early seeding. In contrast to this phenomena, Chilbo, Suwon ＃ 4, Suwon ＃ 6 and Yungwolyukak expressed low valid tiller ratio in general, and also exhibited the same tendency in late seeding date. 12. Number of grains per spike was increased by increasing fertilizer level and decreased by increasing seeding rate. Among the seeding date tested. October 21 (1969) and October 11 (1970) showed lowest number of grains per spike which was increased in both early seeding and late seeding date. There were no definite tendencies observed along with seeding date differences in respective varieties tested. 13. Variation of 1000 grain weight due to fertilizer level applied, seeding date and seeding rate was not so high as number of grains per spike and number of heads per $\m^2$, but exhibited high year variation. Increased seeding rate decreased the 1000 grain weight. Among the varieties tested Chilbo and Buheung expressed heavy grain weight, while Suwon ＃ 18, Hangmi and Yuegi showed comparatively light grain weight. 14. Optimum seeding date in Suwon area was around October 1 to October 11. Yield was generally increased by increasing fertilizer level. Yield decrease due to early seeding was compensated in certain extent by increased fertilizer application. 15. Yield variations due to seeding rate differences were almost negligible compare to the variations due to fertilizer level and seeding date. In either early seeding or law fertilizer level yield variation due to seeding rate was not so remarkable. Increment of fertilizer application was more effective for yield increase especially at increased seeding rate. And also increased seeding rate fairly compensated the decrease of yield in late seeding date. 16. Optimum seeding rate was considered to be around 18-26 liters per 10a at N-P-K=10.5-6-6 kg/10a fertilizer level considering yield stabilization. 17. Varietal differences in optimum seeding date was quite remarkable Suwon ＃ 6, Suwon ＃ 4. Buheung noted high yield at early seeding and Suwon ＃ 18, Yuegi and Hangmi yielded higher in seeding date of October 10. However, Buheung showed late seeding adaptability. 18. Highly significant positive correlations were observed between yield and yield components in all treatments. However, this correlation coefficient was increased positively by increased fertilizer level and decreased by increased seeding rate. Significant negative correlation coefficients were estimated between yield and number of grains per spike, since increased number of heads per m2 at the same level of fertilizer tends to decrease the number of grains per spike. Comparatively low correlation coefficients were estimated between 1000 grain weight and yield. 19. No significant relations in terms of correlation coefficients was observed between number of heads per $\m^2$ and 1000 grain weight or number of grains per head.

• Korean Journal of Agricultural Science
• /
• v.4 no.2
• /
• pp.254-282
• /
• 1977

To obtain information on the inheritance of the quantitative characters related with the vegetative and reproductive growth of rice, the $F_1$ seeds were obtained in 1974 from the all possible combinations of the diallel crosses among five leading rice varieties : Nongbaek, Tongil, Palgueng, Mangyeong and Gimmaze. The $F_1$'s including reciprocals and parents were grown under the standard cultivation method at Chungnam Provincial Office of Rural Development in 1975. The arrangement of experimental plots was randomized block design with 3 replications and 12 characters were used for the analysis. Analytical procedure for genetic components was followed the Griffing's and Hayman's methods and the results obtained are summarized as follows. 1. In all $F_1$'s of Tongil crosses, the longer duration to heading was due to dominant effect of Tongil and each $F_1$ showed high heterosis in delaying the heading time. It was assumed that non-allelic gene action besides dominant gene effect might be involed in days to heading character. However, in all $F_1$'s from the crosses among parents excluding Tongil the shorter duration was due to dominant gene action and the degree of dominance was partial, since dominance effects were not greater than the additive effect. The non-allelic gene interaction was not significant. Considering the results mentioned above, it was regarded that there were two kinds of Significantly different genetic systems in the days to heading. 2. The rate of heterosis was significantly different depending upon the parents used in the crosses. For instance, the $F_1$'s from Togil cross showed high rate of heterosis in longer culm. Compared to short culm, longer culm was due to recesive gene action and short culm was due to recesive gene action. The dominant gene effect was greater than the additive gene effect in culm length. The narrow sense of heretability was very low and the maternal effects as well as reciprocal effects were significantly recognized. 3. The lenght of the of the uppermost internode of each $F_1$ plant was a little lorger than these of respective parental means or same as those of parents having long internodes, indicating partial dominance in the direction of lengthening the uppermost internodes. The additive gene effects on the uppermost internode was greater than the dominance gene effect. The narrow as well as broad sense of heritabilities for the character of the uppermost internode were very high. There were significant maternal and reciprocal effect in the uppermost internode. 4. The gene action for the flag leaf angle was rather dominance in a way of getting narrower angle. However, in the Palgueng combinations, heterosis of $F_1$ was observed in both narrow and wide angles of the flag leaf. The dominant effects were greater than the additive effects on the flag leaf angle. There were observed also a great deal of non-allelic gene interacticn on the inheritance of the flag leaf angle. 5. Even though the dominant gene action on the length and width of flag leaf was effective in increasing the length or width of the flag leaf, there were found various degrees of hetercsis depending upon the cross combination. Over-dominant gene effect were observed in the inheritance of length of the flag leaf, while additive gene effects was found in the inheritance of the width of the flag leaf. High degree of heretabilities, either narrow or broad sense, were found in both length and width of the flag leaf. No maternal and reciprocal effect were found in both characters. 6. When Tongil was used as one parent in the cross, the length of panicle of $F_1$'s was remarkedly longer than that of parents. In other cross comination, the length of panicle of $F_1$'s was close to the parental mean values. Rather greater dominent gene effect than additive gene effect was observed in the inheritance of panicle length and the dominant gene was effective in increasing the panicle length. 7. The effect of dominant genes was effective in increasing the number of panicles. The degree of heterosis was largely dependent on the cross combination. The effect of dominant gene in the inheritance of panicle number was a little greater than that of additive genes, and the inheritance of panicle number was assumed to be due to complete dominant gene effects. Significantly high maternal and reciprocal effects were found in the character studied. 8. There were minus and plus values of heterosis in the kernel number per panicle depending upon the cross combination. The mean dominant effect was effective in increasing the kernel number per panicle, the degree of dominant effect varied with cross combination. The dominant gene effect and non-allelic gene interaction were found in the inheritance of the kernel number per panicle. 9. Genetic studies were impossible for the maturing ratio, because of environmental effects such as hazards delaying heads. The dominant gene effect was responsible for improving the maturing ratio in all the cross combinations excluding Tongil 10. The heavier 1000 grain weight was due to dominant gene effects. The additive gene effects were greater than the dominant gene effect in the 1000 grain weight, indicating that partial dominance was responsible for increasing the 1000 grain weight. The heritabilites, either narrow or broad sense of, were high for the grain weight and maternal or reciprocal effects were not recognized. 11. When Tongil was used as parent, the straw weight was showing high heterosis in the direction of increasing the weight. But in other crosses, the straw weight of $F_1$'s was lower than those of parental mean values. The direction of dominant gene effect was plus or minus depending upon the cross combinations. The degree of dominance was also depending on the cross combination, and apparently high nonallelic gene interaction was observed.