Comparison of Volatile and Nonvolatile Compounds in Rice Fermented by Different Lactic Acid Bacteria.

The production of rice-based beverages fermented by lactic acid bacteria (LAB) can increase the consumption of rice in the form of a dairy replacement. This study investigated volatile and nonvolatile components in rice fermented by 12 different LABs. Volatile compounds of fermented rice samples were analyzed using gas chromatography-mass spectrometry (GC-MS) combined with solid-phase microextraction (SPME), while nonvolatile compounds were determined using gas chromatography-time-of-flight/mass spectrometry (GC-TOF/MS) after derivatization. The 47 identified volatile compounds included acids, aldehydes, esters, furan derivatives, ketones, alcohols, benzene and benzene derivatives, hydrocarbons, and terpenes, while the 37 identified nonvolatile components included amino acids, organic acids, and carbohydrates. The profiles of volatile and nonvolatile components generally differed significantly between obligatorily homofermentative/facultatively heterofermentative LAB and obligatorily heterofermentative LAB. The rice sample fermented by Lactobacillus sakei (RTCL16) was clearly differentiated from the other samples on principal component analysis (PCA) plots. The results of PCA revealed that the rice samples fermented by LABs could be distinguished according to microbial strains.

Determination of methanol and fusel oils in various types of wines distributed in Korea.

The contents of methanol and fusel oils in various types of wines were determined using headspace-gas chromatography (HS-GC). The HS-GC analysis method showed good linearity, high precision and accuracy, and low LOQ and LOD values. The methanol content in 289 types of wines ranged from not detected (ND) to 333.84 mg/kg, and was higher in Korean grape wines than in imported grape wines. Among fusel oils, the contents of 1-propanol (23.61-84.23 mg/kg) and isobutanol (34.98-111.39 mg/kg) were slightly higher in Korean wild grape wines, whereas that of isobutanol (ND to 55.26 mg/kg) was slightly lower in Korean black raspberry wine than in the other wines. The contents of amyl alcohol were lower in Korean plum wine and Korean black raspberry wine than in all of the wines included in the present study, and highest in imported grape wines.

Effects of soaking treatment on the acrylamide and inulin contents of Jerusalem artichoke tea and its antioxidant activity.

There are several studies that show that large amounts of acrylamide are detected in Jerusalem artichoke (Helianthus tuberosus L.) tea. This study examined acrylamide, inulin content and antioxidant properties of Jerusalem artichoke tea brewed in different conditions. Uniformly sliced Jerusalem artichokes were soaked in different salt and acidic solutions for 60 min at 20 °C and extracted with hot or cold water. The acrylamide content was analyzed by high-performance liquid chromatography-tandem mass spectrometry. The Inulin content and antioxidant activity were analyzed by spectrophotometer. Soaking significantly reduced acrylamide levels (p < 0.05) with the largest decrease observed for acetic acid, whereas the effects of all soaking treatments on inulin content were similar. Teas brewed using small-particle-size samples and hot water exhibited the highest acrylamide/inulin levels and antioxidant activity. Consequently, The most suitable treatment for Jerusalem Artichoke tea preparation was 1-h soaking in 1% acetic acid at 20 °C.

Effects of extraction conditions on acrylamide/furan content, antioxidant activity, and sensory properties of cold brew coffee.

The effects of extraction conditions on the acrylamide/furan content, antioxidant activity, and sensory properties of cold brew coffee were probed for samples prepared by steeping and dripping at various temperatures and for different times. Sensory properties were evaluated using a nine-point hedonic scale and an overall preference ranking test. Samples prepared by 3-h extraction featured the lowest acrylamide levels, while the lowest furan contents were observed for samples prepared by 24-h steeping and 12-h dripping. Among steeping-prepared samples, that extracted for 24 h showed the highest total phenol content, although no significant differences were observed for extraction times above 12 h, with a similar trend observed for ABTS free radical anion scavenging activity. Thus, the contents of bioactive and hazardous chemicals as well as sensory properties were found to be influenced by various extraction conditions.

Effects of Thawing and Frying Methods on the Formation of Acrylamide and Polycyclic Aromatic Hydrocarbons in Chicken Meat.

Air frying is commonly used as a substitute for deep-fat frying. However, few studies have examined the effect of air frying on the formation of potential carcinogens in foodstuffs. This study aimed to investigate the formation of acrylamide and four types of polycyclic aromatic hydrocarbons (PAHs) in air-fried and deep-fat-fried chicken breasts, thighs, and wings thawed using different methods, i.e., by using a microwave or a refrigerator, or by water immersion. The acrylamide and PAHs were analyzed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS), respectively. Deep-fat-fried chicken meat had higher acrylamide (n.d.-6.19 µg/kg) and total PAH (2.64-3.17 µg/kg) air-fried chicken meat (n.d.-3.49 µg/kg and 1.96-2.71 µg/kg). However, the thawing method did not significantly affect the formation of either acrylamide or PAHs. No significant differences in the acrylamide contents were observed among the chicken meat parts, however, the highest PAH contents were found in chicken wings. Thus, the results demonstrated that air frying could reduce the formation of acrylamide and PAHs in chicken meat in comparison with deep-fat frying.

Validation of analytical methods for organochlorine pesticide detection in shellfish and cephalopods by GC-MS/MS.

This study validated the analysis of organochlorine pesticides (OCPs) in shellfish and cephalopods using a gas chromatograph equipped with a mass spectrometry (GC-MS/MS), and monitored residual pesticide levels. The QuEChERS method was used to analyze OCPs and was validated by checking the linearity, limit of detection (LOD), limit of quantitation (LOQ), accuracy, and precision. Octopus minor and Venerupis philippinarum, were purchased from four cities in the South Korean peninsula. The LOD values were 0.10-0.80 ng/g in shellfish and 0.21-0.77 ng/g in cephalopods, while the LOQ values were 0.31-2.41 ng/g in shellfish and 0.63-2.33 ng/g in cephalopods. Accuracy ranged from 83.5 to 117.4% and 79.8 to 118.4%, and precision ranged from 0.3 to 27.5% and 1.2 to 27.9%, in shellfish and cephalopods, respectively, conforming to the Codex Alimentarius Commission guidelines. Although residual OCP levels were below detection limits, the QuEChERS method may be effective for analyzing the OCPs in shellfish and cephalopods.

Comparison of acrylamide and furan concentrations, antioxidant activities, and volatile profiles in cold or hot brew coffees.

The aim of this study was to investigate the formation of furan and acrylamide and to compare antioxidant capacities and volatile compounds in cold or hot brewed coffees. Cold brews were prepared at 5 °C and 20 °C for 12 h. using steeping and dripping, and hot brews were prepared at 80 °C and 95 °C for 5 min. using the pour-over method. Furan contents of cold steeping at 5 °C and hot brewed at 80 °C showed the higher levels significantly (p < 0.05), which were 17.0 ± 0.5 and 10.6 ± 0.1 ng/mL, respectively. However, acrylamide contents in cold steeping at 5 °C and hot brew at 80 °C showed lower levels, which were 4.1 ± 0.4 and 3.5 ± 0.1 ng/mL respectively. Cold brews at 20 °C showed the highest levels of antioxidant activities while hot brews showed similar levels with cold brews at 5 °C. This study confirms that levels of different beneficial and hazardous chemical compounds could be manipulated by adjusting the coffee extraction conditions.

Origin and organ-specific bioaccumulation pattern of perfluorinated alkyl substances in crabs.

Consumption of seafood is a major contributor to perfluorinated alkyl substances (PFASs) exposure. Crabs contain high levels of PFASs, and different PFASs are concentrated in their tissues depending on their habitat. Despite South Korea importing huge quantities of crabs, no investigation has been conducted on the effect of PFAS exposure. This study investigated the risk of exposure to PFASs when ingesting crabs. To determine the risk of exposure, 19 different PFAS species were measured in the edible parts (body, legs, offal, and eggs) of crabs originating from South Korea (n = 17), China (n = 14), India (n = 7), and Pakistan (n = 31), which were distributed in the fish markets of South Korea. The results revealed that, in contrast to short-chain PFASs, long-chain PFASs (PFCAs≥8, PFSAs≥6, and perfluorooactane sulfonamidoacetic acids (FOSAAs)≥8) were detected in crab samples from all four countries of origin, and in all the edible parts except for the legs. Perfluorooctanoic acid (PFOA; 16.9 ng/g in South Korea, 9.42 ng/g in China) and perfluoro-n-tridecanoic acid (PFTrDA; 5.35 ng/g in South Korea, 2.40 ng/g in China) were the predominant perfluoroalkyl carboxylic acids (PFCAs) detected in the crabs originating from South Korea and China, and perfluorooctane sulfonic acid (PFOS; 7.02 ng/g in Pakistan, 5.88 ng/g in India) was the predominant perfluoroalkyl sulfonic acids (PFSAs) detected in crabs originating from Pakistan and India. These results indicate that PFASs that are accumulated in crabs differ depending on the ocean from which they originate. The concentrations of PFOA and PFOS were significantly higher in the eggs and offal than in the legs and body of the crab. The average daily intake of PFOA and PFOS in South Koreans ranges from 0.01% to 0.07% based on the tolerable daily intake of EFSA and MFDS. These results establish the PFAS profiles and risk assessment of crabs that are distributed in South Korea.

Effect of washing, soaking, and cooking methods on perfluorinated compounds in mackerel (Scomber japonicus).

Perfluorinated compounds (PFCs) are environmental pollutants, and dietary intake is a major route of human exposure to them. We aimed to see the effects of washing, soaking, and cooking (grilling, braising, frying, and steaming) on the change of PFCs in mackerel fillets and PFCs before and after each treatment were analyzed using LC-MS/MS. Washing resulted in a decrease in the PFC content of mackerel (average 74%) comparing to control. Among the 19 PFCs detected, perfluorobutanoic acid and perfluorotridecanoic acid (PFTrDA) were found to be abundant after washing. Soaking mackerel in sake reduced its PFC content by 51%, whereas soaking in rice-washed solution reduced by 80% comparing to control. All the four cooking methods were effective in reducing the PFC content of mackerel. The degree by which the PFC content decreased varied with the cooking method: grilling (91%), steaming (75%), frying (58%), and braising (47%) comparing to uncooked sample. In addition, when mackerel was braised with potato, PFCs decreased more in fillet than the ones without potato. PFCs in potato increased after cooking with mackerel. The excessive consumption through the mackerel was 0.1997 ng/kg bw/day and 0.7987 ng/kg bw/day, respectively. These exposure levels were well below the tolerable daily intake values of both compounds (PFOS, 150 ng/kg bw/day; PFOA, 1,500 ng/kg bw/day). The results of this study indicated that employing appropriate pretreatment and cooking methods could be an effective way to reduce the dietary exposure to PFCs in mackerel.

Reduction of total, organic, and inorganic arsenic content in Hizikia fusiforme (Hijiki).

This study aimed to evaluate the reduction of total, organic, and inorganic arsenic content in Hizikia fusiforme (hijiki). Initially, the six most common arsenic compounds in hijiki and its organs were evaluated, among which only arsenate and arsenobetaine were detected. Thereafter, the entire plant, including the stalk and leaves, was treated with heat and NaCl solution, individually and in combination. Heating at 90 °C for 5 min significantly reduced arsenic content in hijiki by approximately 33-80%. Treatment with NaCl solution significantly reduced arsenic content in hijiki, except for arsenobetaine content in the stalk. Combinatorial treatment further decreased arsenic content by more than 5-20%. In conclusion, consumption of hijiki after boiling at 90 °C and soaking in 2% NaCl solution reduces the intake of inorganic arsenic by consumers.

Comparing levels of perfluorinated compounds in processed marine products.

Perfluorinated compounds (PFCs) are widely distributed in nature and have many applications due to their unique chemical and physicochemical properties. While, PFCs are present in soil, water, and air, their pathway for entry into the human body is circumstantially via contaminated food. The demand for seafood has been increasing. In this study, we investigated via LC-MS/MS, the content of 19 different types of PFCs in 302 samples belonging to five different categories of the typical South Korean seafood. The highest levels of PFOA, PFTrDA, PFOS, and PFPeA were found in dried seafood, canned and salted seafood, processed fish food, and seasoned laver, respectively. The levels of PFOA and PFOS were compared on the basis of various criteria including the nomenclature, biological classification, and habitat of the source of seafood. High levels of PFOA and PFOS were detected in anchovy, sea squirt, and mackerel based on the nomenclature of raw seafood, in crustaceans based on the biological classification, and in demersal organisms based on the habitat. The human intake values of PFOA and PFOS from the processed marine products in South Korea were lower than the tolerable daily intake, indicating that the consumption of these processed seafood poses no immediate harm.

Biogenic amines in foods.

Biogenic amines are produced by bacterial decarboxylation of corresponding amino acids in foods. Concentration of biogenic amines in fermented food products is affected by several factors in the manufacturing process, including hygienic of raw materials, microbial composition, fermentation condition, and the duration of fermentation. Intake of low amount of biogenic amines normally does not have harmful effect on human health. However, when their amount in food is too high and detoxification ability is inhibited or disturbed, biogenic amines could cause problem. To control concentration of BAs in food, decarboxylase activity for amino acids can be regulated. Levels of BAs can be reduced by several methods such as packaging, additives, hydrostatic pressure, irradiation, pasteurization, smoking, starter culture, oxidizing formed biogenic amine, and temperature. The objective of this review paper was to collect, summarize, and discuss necessary information or useful data based on previous studies in terms of BAs in various foods.

Systematic Investigation of the Reduction of Inorganic Arsenic and Bioactive Nutrients in Rice with Various Cooking Techniques.

The objectives of this study were to investigate the effect of polishing, stirring and rinsing, soaking, or pressure-steam cooking on total organic and inorganic arsenic content and to measure daily inorganic arsenic exposure and nutrient values from consumption of rice prepared under the optimal process. With increasing numbers of rinses and times stirred per rinse, the total arsenic content significantly decreased by 27.6% in brown rice and 39.0% in white rice with 10% degree of polishing (10DOP%). The increase in ratio of water to rice from 1.5:1 to 6:1 reduced total arsenic by 4.4 to 7.5%, depending on soaking time. The total arsenic concentrations found in samples prepared using the optimal process for cooked brown rice and for white rice with 5DOP%, 7DOP%, and 10DOP% were 56.1, 49.6, 52.0, and 42.0%, respectively, compared with those after bran residues were removed. The concentration of total dietary fiber in 10DOP% white and brown rice was 0.34 mg/100 g (54.7% reduction) and 2.52 mg/100 g (24.8% reduction) after the cooking process, respectively. Results from the current study suggest that the optimal cooking process could maximize the reduction of arsenic contents and, at the same time, minimize the loss of nutrients from rice.

Determination of total arsenic content and arsenic speciation in different types of rice.

The objectives of this study was to examine the amount of total arsenic and arsenic speciation in different types of rice from two areas in Korea using inductively coupled plasma/mass spectrometer (ICP-MS) and high performance liquid chromatography-ICP/MS (HPLC-ICP/MS) and estimate the potential health risk from rice consumption. Brown rice (0% of degree of polishing, DOP%) contained the highest amount of total arsenic followed by 5, 7 and 10 DOP% white rice. Among the arsenic species, As(III) was predominantly detected in brown (0 DOP%) and white rice (10 DOP%), with concentrations ranging from 28.51±0.71 to 51.91±1.13 µg/kg in region A and from 62.1 to 130.4 µg/kg in region B. While estimating the daily arsenic exposure from consumption of polished rice, the expected daily exposure of inorganic arsenic from brown and 10 DOP% white rice was found to be below benchmark dose modeling value for a 0.5% increased incidence of lung cancer (BMDL0.5) (3.0 µg/kg bw per day). Therefore, arsenic in rice, particularly, As(III), tends to accumulate in the outer layer of rice.

Bactericidal Effect of Calcium Oxide (Scallop-Shell Powder) Against Pseudomonas aeruginosa Biofilm on Quail Egg Shell, Stainless Steel, Plastic, and Rubber.

The aim of this study was to evaluate the bactericidal effect of calcium oxide (CaO) against Pseudomonas aeruginosa biofilms on quail eggshells and major egg contacting surfaces (stainless steel, plastic, and rubber). The samples were subjected to CaO treatments (0%, 0.01%, 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, and 0.30%) for 1 min. All the CaO treatments significantly reduced P. aeruginosa biofilms on all tested surfaces as compared to controls. In comparison of biofilm stability, the strongest and most resistant biofilm was formed on eggshell against the CaO treatment, followed by rubber, stainless steel, and plastic. In evaluation of bactericidal effect, the largest reduction (3.16 log CFU) was observed in plastic even at the lowest concentration of CaO (0.01%), whereas the least reduction was found in eggshells, regardless of CaO concentration. In addition, stainless steel showed a significant reduction in biofilm formation at all concentrations except 0.10% to 0.15% CaO. At 0.30% CaO, the reduction of P. aeruginosa in biofilms on stainless steel, plastic, rubber, and eggshell were 5.48, 6.37, 4.87, and 3.14 log CFU/cm2 (CFU/egg), respectively. Biofilm reduction after CaO treatment was also observed by field emission scanning electron microscopy (FE-SEM). Based on the FE-SEM images, we observed that P. aeruginosa biofilms formed compact aggregations on eggshell surfaces with CaO treatments up to 0.30%. More specifically, a 0.20% CaO treatment resulted in the reductions of 3 to 6 log CFU in all materials.

Simple detection of residual enrofloxacin in meat products using microparticles and biochips.

A simple and sensitive method for detecting enrofloxacin, a major veterinary fluoroquinolone, was developed. Monoclonal antibody specific for enrofloxacin was immobilised on a chip and fluorescent dye-labelled microparticles were covalently bound to the enrofloxacin molecules. Enrofloxacin in solution competes with the microparticle-immobilised enrofloxacin (enroMPs) to bind to the antibody on the chip. The presence of enrofloxacin was verified by detecting the fluorescence of enrofloxacin-bound microparticles. Under optimum conditions, a high dynamic range was achieved at enrofloxacin concentrations ranging from 1 to 1000 µg kg(-1). The limits of detection and quantification for standard solutions were 5 and 20 µg kg(-1) respectively, which are markedly lower than the maximum residue limit. Using simple extraction methods, recoveries from fortified beef, pork and chicken samples were 43.4-62.3%. This novel method also enabled approximate quantification of enrofloxacin concentration: the enroMP signal intensity decreased with increasing enrofloxacin concentration. Because of its sensitivity, specificity, simplicity and rapidity, the method described herein will facilitate the detection and approximate quantification of enrofloxacin residues in foods in a high-throughput manner.

Comparison of indicators of microbial quality of meat during aerobic cold storage.

This study was undertaken to evaluate various indicators for the prediction of the microbial quality of pork and beef loins during cold storage at 0 and 4 degrees C under aerobic conditions. Fresh loins of beef and pork were packaged aerobically and stored at 0 +/- 1 degrees C for 22 days and at 4 +/- 1 degrees C for 12 days or until the total plate counts (TPCs) for these loins exceeded 10(8) CFU/ml. During storage, samples were taken periodically for the measurement of TPCs, psychrotrophic bacterial counts, amine contents, volatile basic nitrogen (VBN) values, thiobarbituric acid values, D-glucose contents, L-lactate contents, pH, and electrical conductivity. Correlation coefficients were ca. 0.90 for all indicators except pH and conductivity. However, VBN and D-glucose contents showed the best correlation with bacterial counts at both temperatures for both beef and pork. Therefore, VBN and D-glucose could potentially be used as indicators in predicting the microbial quality of beef and pork during chilled storage under aerobic conditions.

Infrared sensor-based aerosol sanitization system for controlling Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on fresh produce.

An economical aerosol sanitization system was developed based on sensor technology for minimizing sanitizer usage, while maintaining bactericidal efficacy. Aerosol intensity in a system chamber was controlled by a position-sensitive device and its infrared value range. The effectiveness of the infrared sensor-based aerosolization (ISA) system to inactivate Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on spinach leaf surfaces was compared with conventional aerosolization (full-time aerosol treated), and the amount of sanitizer consumed was determined after operation. Three pathogens artificially inoculated onto spinach leaf surfaces were treated with aerosolized peracetic acid (400 ppm) for 15, 30, 45, and 60 min at room temperature (22 ± 2°C). Using the ISA system, inactivation levels of the three pathogens were equal or better than treatment with conventional full-time aerosolization. However, the amount of sanitizer consumed was reduced by ca. 40% using the ISA system. The results of this study suggest that an aerosol sanitization system combined with infrared sensor technology could be used for transportation and storage of fresh produce efficiently and economically as a practical commercial intervention.

Bacteriological quality of vegetables from organic and conventional production in different areas of Korea.

Foods grown in organic production systems have been described as representing an increased risk to public health compared with foods from conventional production. Leafy vegetables (spinach, romaine lettuce, and green sesame leaves) grown in organic and conventional systems were collected from various areas in Korea and examined using standard culture methods to compare the microbiological quality of the produce grown in the two agricultural systems. The 354 samples of these leafy vegetables were analyzed for levels of indicator bacteria (aerobic bacteria, coliforms, and Escherichia coli) and the prevalence of the pathogens Staphylococcus aureus, E. coli O157:H7, Listeria monocytogenes, Bacillus cereus, and Salmonella. Aerobic bacteria and coliforms were detected in all vegetable types, but nonpathogenic E. coli was below the limit of detection in all samples. B. cereus was the most prevalent pathogen, found on 7 (11.1%) of the 63 organic spinach samples. The prevalence of S. aureus was highest in organic sesame leaves; it was found on 5 (8.0%) of the 63 samples. The prevalence of L. monocytogenes was highest on organic romaine lettuce and spinach; it was found in 4 (6.4%) of 63 samples of each type of vegetable. E. coli O157:H7 found on only 1 (1.58%) of 55 conventional spinach samples. These results suggest that farming type at most only slightly affects the hygienic quality of leafy vegetables, and no effect was found for sample collection area. Salmonella was not isolated from any of the conventional or organic leafy vegetables. These results do not support the hypothesis that organic produce poses a substantially greater risk of pathogen contamination than does conventional produce.

Identification of human and animal fecal contamination after rainfall in the Han River, Korea.

We investigated the effect of rainfall on the levels and sources of microbial contamination in the Han River, Korea. Thirty-four samples were collected at two sampling sites located upstream and downstream in the river from July 2010 to February 2011. Various fecal indicator microorganisms, including total coliform, fecal coliform, Escherichia coli, Enterococcus spp., somatic and male-specific (F+) coliphage, and four major enteric viruses were analyzed. Rainfall was positively correlated with the levels of fecal coliform and norovirus at both sampling sites. Additionally, rainfall was positively correlated with the levels of total coliform, E. coli, Enterococcus spp., and F+ coliphage at the upstream site. To identify the source of fecal contamination, microbial source tracking (MST) was conducted using both male-specific (F+) RNA coliphage and the Enterococcus faecium esp gene as previously described. Our results clearly indicated that the majority of fecal contamination at the downstream Han River site was from a human source. At the upstream sampling site, contamination from human fecal matter was very limited; however, fecal contamination from non-point animal sources increased following rainfall. In conclusion, our data suggest that rainfall significantly affects the level and source of fecal contamination in the Han River, Korea.