Risk ranking must be determined for various hazards/food combinations to conduct microbial risk management effectively. Risk Ranger is a simple, easy-to-use calculation tool developed in Microsoft Excel and designed to rank the risk (low, medium, and high) for semi-quantitative microbial risk assessment. The user is required to answer 11 questions in Risk Ranger related to 1) severity of the hazard, 2) likelihood of a disease-causing dose of the hazard being present in the meal, and 3) the probability of exposure to the hazard in a defined time. This study determined the risk ranking for twenty three combinations of foodborne pathogens/potentially hazardous foods (PHFs) using a Risk Ranger. In this study, pathogenic E. coli in fresh cut produce salad was scored as 79, which was the highest rank among the 23 combinations of the foodborne pathogens and PHFs. On the other hand, zero risk was obtained with V. parahaemolyticus in sushi, Salmonella in meat products and E. coli O157:H7 in hamburger patties. Although Risk Ranger is very simple method to rate the risk of foodborne pathogens and PHFs combination, the accuracy of result was mainly affected by the availability and accuracy of data in the literature. According to the result of literature review, the data are needed for contamination rate of raw materials, consumption amount/frequency of PHFs, and the effect of processing on pathogen. Risk ranking must be continuously revalidated with new data.
This study was conducted to investigate the residue amount of harmful materials on the 113 commercial fruit teas (Gugija, Omija, Sansuyu) in Gwangju area. It was performed using the GC-ECD, GC-NPD, GCMSD and the LC-UVD, LC-FLD, LC-MSD to analyze 200 pesticides. The heavy metals were determined using a Mercury analyzer and AAS. The sulfur dioxides were analyzed by modified Monnier-Williams method. The residual pesticides were detected in 4 samples (Gugija). The mean values of heavy metal contents (mg/kg) were Pb, 0.024; Cd,0.031; As, 0.010; Hg, 0.003. The measured values of Pb, Cd, As, Hg showed within MRLs. The sulfur dioxides were over MRLs in 4 samples (Gugija). These results will be used to establish on the regulation of commercial fruit teas in Gwangju area.
Plantago asiatica L. (PA), which is widely distributed in Korea, Japan and China, has traditionally been used as a popular folk medicine for the treatment of liver diseases. A variety of activities of PA was reported, that is hepatoprotective, anti-inflammatory, anti-glycation and anti-oxidant effect. Ferric nitrilotriacetate (Fe-NTA) is a potent nephrotoxic agent and has been reported to induce renal proximal tubular necrosis. In the present study, pretreatment with PA extract (PAE) in Wistar rat followed by Fe-NTA i.p. treatment (13.5 mg Fe/kg body weight) was performed to detect the renal protective effect of PAE. Only Fe-NTA treated group showed increases in the level of serum blood urea nitrogen (BUN) and serum creatinine (Cr), and renal tissue malondialdehyde (MDA), product of lipid peroxidation. Moreover, the level of biomarkers indicate the antioxidants status, reduced glutathione (GSH), glutathione-S-transferase (GST) and glutathione reductase (GR) were decreased. However, PAE pre-treated group showed decreases in the levels of serum BUN, serum Cr and renal tissue MDA in concentration dependent manner and increases in the level of GSH, GST and GR. These results are significantly different (p < 0.05) to the other groups. Our data suggest that PAE may be used as an chemopreventive material against Fe-NTA-mediated renal oxidative stress.
In this study, two duplex real-time PCR approach with melting curve analysis is presented for the detection of Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp. and Staphylococcus aureus, which are important food-borne bacterial pathogens usually present in fresh and/or minimally processed vegetables. Reaction conditions were adjusted for the simultaneous amplification and detection of specific fragments in the β-glucuronidase (uidA, E. coli), thermonuclease (nuc, S. aureus), hemolycin (hly, L. monocytogenes) and tetrathionate reductase (ttr, Salmonella spp.) genes. Melting curve analysis using a SYBR Green I real-time PCR approach showed characteristic Tm values demonstrating the specific and efficient amplification of the four pathogens; 80.6 ± 0.9 ℃,86.9 ± 0.5 ℃, 80.4 ± 0.6 ℃ and 88.1 ± 0.11 ℃ for S. aureus, E. coli O157:H7, L. monocytogenes and Salmonella spp.,respectively. For all the pathogens, the two duplex, real-time PCR was equally sensitive to uniplex real-time PCR,using same amounts of purified DNA, and allowed detection of 10 genome equivalents. When our established duplex real-time PCR assay was applied to artificially inoculated fresh lettuce, the detection limit was 10³ CFU/g for each of these pathogens without enrichment. The results from this study showed that the developed duplex real-time PCR with melting curve analysis is promising as a rapid and cost-effective test method for improving food safety.
Predictive mathematical models were developed for predicting the kinetics of growth of Listeria monocytogenes in smoked salmon, which is the popular ready-to-eat foods in the world, as a function of temperature (4, 10, 20 and 30℃). At these storage temperature, the primary growth curve fit well (r² = 0.989~0.996) to a Gompertz equation to obtain specific growth rate (SGR) and lag time (LT). The Polynomial model for natural logarithm transformation of the SGR and LT as a function of temperature was obtained by nonlinear regression (Prism, version 4.0,GraphPad Software). Results indicate L. monocytogenes growth was affected by temperature mainly, and SGR model equation is 365.3-31.94*Temperature+0.6661*Temperature^2 and LT model equation is 0.1162-0.01674*Temperature+0.0009303*Temperature^2. As storage temperature decreased 30℃ to 4℃, SGR decreased and LT increased respectively. Polynomial model was identified as appropriate secondary model for SGR and LT on the basis of most statistical indices such as bias factor (1.01 by SGR, 1.55 by LT) and accuracy factor (1.03 by SGR, 1.58 by LT).
Melamine has raised international concerns for its catastrophic health effects from tainted infant formula. This report concerns the developmental validation of a sensitive HPLC/MS/MS and GC/MS methods about melamine and cyanuric acid in human urine and serum. Analytical detection ranges of LC/MS was from 0.2 to 5.0 ng/mL and 2.0 to 60.0 ng/mL about melamine and cyanuric acid, respectively. The limits of quantification and confirmation are 0.2 ng/mL for both analytes in human urine and serum by LC/MS/MS. The range of recovery was 91.6%, and 107.6% for cyanuric acid and melamine in urine, respectively. The range of precision coefficient variation was from 2.0%, to 11.8% for cyanuric acid and melamine in urine. The range of recovery was from 94.9%, to 119.0% about cyanuric acid and melamine in serum, respectively. The range of precision coefficient variation from was 3.7%, and 13.5% about cyanuric acid and melamine in serum. Analytical detection ranges of GC/MS were 5.0 to 100.0 ng/mL about melamine and cyanuric acid, respectively. The limits of quantification and confirmation are 5.0 ng/mL for both analytes in human urine and serum by GC/MS. The range of recovery was from 83.7%, to 114.5% for cyanuric acid and melamine in urine, respectively. The range of precision coefficient variation was 3.5%, and 10.7% for cyanuric acid and melamine in urine. The range of recovery was 94.4%, and 110.7% for cyanuric acid and melamine in serum,respectively. The range of precision coefficient variation from was 3.9%, and 13.8% for cyanuric acid and melamine in serum. Several changes were taken to optimize performance by this method.
An isocratic high performance liquid chromatography (HPLC) method for routine analysis of deoxynivalenol in noodles was validated and estimated the measurement uncertainty. Noodles (dried noodle and ramyeon) were analyzed by HPLC-ultraviolet detection using immunoaffinity column for clean-up. The limits of detection (LOD) and quantification (LOQ) were 7.5 μg/kg and 18.8 μg/kg, respectively. The calibration curve showed a good linearity, with correlation coefficients r² of 0.9999 in the concentration range from 20 to 500 μg/kg. Recoveries and Repeatabilities expressed as coefficients of variation (CV) spiked with 200 and 500 μg/kg were 82 ± 2.7% and 87 ± 1.3% in dried noodle, and 97 ± 1.6% and 91 ± 12.0% in ramyeon, respectively. The uncertainty sources in measurement process were identified as sample weight, final volume, and sample concentration in extraction volume as well as components such as standard stock solution, working standard solution, 5 standard solutions, calibration curve,matrix, and instrument. Deoxynivalenol concentration and expanded uncertainty in two matrixes spiked with 200 μg/kg and 500 μg/kg were estimated to be 163.8 ± 52.1 and 435.2 ± 91.6 μg/kg for dried noodle, and 194.3 ± 33.0 and 453.2 ± 91.1 μg/kg for ramyeon using a coverage factor of two which gives a level of statistical confidence with approximately 95%. The most influential component among uncertainty sources was the recovery of matrix, followed by calibration curve.
Betulinic acid (BA), a naturally occurring triterpene found in the bark of the white birch tree, has been investigated to induce apoptosis in various cancer cells and animal models. However, there is no report of the chemopreventive effect of BA in cervical cancer cells. Using KB human cervical cancer cells as a model, we currently show that BA decreases cell viability and induces apoptotic cell death. The mechanism of the BA-induced anti-growth response in KB cells is due to the down-regulation of specificity protein 1 (Sp1) and its downstream targets, myeloid cell leukemia-1(Mcl-1) and survivin. Thus, BA acts as a novel chemopreventive agent through the regulation of Sp1that is highly expressed in tumors.
Inadequate food handling and poor hand hygiene play a major role in the occurrence of foodborne diseases. The objective of this study was to find out if the level of microbial contamination on the hands of food preparers varies by time during their working period. This study focused on the contamination of aerobic plate count,total and fecal coliforms, Escherichia coli, Staphylococcus aureus, and Salmonella spp. Sampling from left hand and right hand of twenty food preparers was done with glove-juice method at every two hours during their work. Microbiological testing was conducted according to the Food Code of Korea. The microbiological load on the hands was changed over time. Samples taken from their hands before work and at 8 hours showed higher levels of bacteria than those taken at 2, 4, and 6 hours during work and/or after work (p < 0.05). The contamination levels of microorganisms were consistently higher in right hand than in left hand. Poor hand hygiene practices were indicated by the positive results for total and fecal coliforms, E. coli, S. aureus, and Salmonella spp. on the hands of some food preparers. This study indicates food preparers' hands can be a vehicle of pathogen during their work. The results of this study emphasize the importance of hand hygiene education and training targeting the food preparers.
The composition of fatty acids in bakery products from 35 bakeries in Seoul was analyzed by GCFID. The contents of crude fat in bakery products were represented 9.54-44.30% in pastries, 14.67-41.22% in cookies and 7.63-28.15% in whipped cream cakes. The total saturated fatty acid content in pastries, cookies and whipped cream cakes were 12.8-75.1%, 8.7-81.6% and 50.2-85.9% respectively. The proportion of trans fatty acids in pastries ranged from 0.00 to 3.37%. Cookies and whipped cream cakes were represented varying amount of trans fatty acid with highest value of 4.55% in cookies and 2.13% in whipped cream cakes. Total estimated daily intakes of fatty acids from pastries and whipped cream cakes were as follows : 1.2 g/day/person for saturated fatty acids and 0.014 g/day/person for trans fatty acids.
Modern people have begun to have the nationwide interest in the rice wine called Makgeolri which is one of the traditional Korean alcoholic liquors. This study was performed to investigate the effects of Sansung Makgeolri extract (SM) on antioxidation together with the determination of pH and dissolved oxygen (DO) in the progress of fermentation in the lipopolysaccharide(LPS)-treated rats. We examined the levels of SOD (superoxide dismutase),CAT (catalase), GPx (glutathione peroxidase) in liver homogenates and the histopathological observations in liver tissue. LPS-treated group markedly decreased the levels of SOD, CAT and GPx. But SM + LPS-treated group significantly increased the levels of them. Furthermore, the antioxidative effects of SM were supported by the histopathological observations in liver tissue which showed severe inflammation and necrosis in LPS-treated group,compared to the attenuated inflammation and necrosis in SM + LPS-treated group. This results suggested that SM could be a candidate of antioxidative material in spite of alcoholic liquors.
Though food safety efforts of the government has been increasing, but the health hazards resulting from food does not stop and thus increases consumers' anxiety and distrust of government. For more reliable safety management, developing analysis and intake measurement methods and strengthening regulatory control with strict criteria is necessary. In addition, as not only the known hazards by now, but also unknown but obvious hazards are simultaneously ongoing in current environments, the unified risk management and health assessment for food, health food and medicines from the media is critical. As risks and damage to health may show up after a long time after exposure,preventive measures and strategies for safety control is also needed.
This study was conducted to develop an appropriated management for safety of children snacks sold around school. Total 598 items as targeted food were collected; 66 biscuits, 320 candies, 57 chocolates, 40 ice creams and 115 beverages. Microbiological hazards such as total aerobic bacteria, Coliforms, Escherichia coli, Bacillus ceruse, Yeasts & molds were measured by analytical method in Korean food code. Total aerobic bacteria and Yeasts & molds were detected in cookies at the level of less than 2.69 and 2.65 log10CFU/g and the detection rates were 54.55 and 62.12%, respectively. Bacillus cereus was detected in 1 snack only at the level of 1.39 log10CFU/g but it was less than Korean microbial standards and specifications (3 log10 CFU/g). Total aerobic bacteria and Yeasts &molds were detected in candies less than 2.86, 3.36 log10CFU/g and the detection rates were 46, 8% respectively. Total aerobic bacteria, Yeast & mold were detected in chocolates at the levels less than 2.52 and 1.87 log10CFU/g and the detection rates were 33 and 22% respectively. Total aerobic bacteria in both ice creams and beverages were detected at the levels less than 3.39 and 1.35 log10CFU/g and the detection rates were 82 and 5% respectively. Coliforms were found in one ice cream (1.39 log10CFU/g) only. The result of this study indicated that all children snacks around school were suitable for microbial standard and specifications in Korean Food Code. However, since most children snacks around school are circulated without proper storage temperature and handing condition, consistent microbial management for children snacks are needed.