An Evaluation of Aflatoxin and Cyclopiazonic Acid Production in Aspergillus oryzae

KIM, NAM YEUN,LEE, JIN HEE,LEE, INHYUNG,JI, GEUN EOG International Association for Food Protection 2014 Journal of food protection Vol.77 No.6

<P>To date, edible fungi such as Aspergillus flavus var. oryzae (A. oryzae) has been considered as safe. However, some strains can produce mycotoxins. Thus, the biosynthetic ability to produce mycotoxins should be reevaluated to determine the safety of edible fungi. We analyzed the production of aflatoxins and cyclopiazonic acid (CPA) from edible fungi such as A. oryzae isolated from various Korean foods using multiplex PCR, enzyme-linked immunosorbent assay, and high-performance liquid chromatography (HPLC). In the multiplex PCR analysis of aflatoxin biosynthetic genes omtB, aflR, ver-1, and omtA, 5 of 19 Aspergillus strains produced all PCR products. Among them, aflatoxin B1 and aflatoxin B2 were detected from only A. flavus KACC 41403 by HPLC. Aflatoxins were not detected from the other four strains that produced all positive PCR bands. Aflatoxin also was not detected from 12 strains that had PCR patterns without aflR or ver-1 and from 2 strains that did not produce any of the expected PCR products. Only the seven A. oryzae strains that produced all of the positive PCR bands including the CPA biosynthetic genes maoA, dmaT, and pks-nrps produced CPA. CPA and aflatoxin production must be evaluated before A. oryzae strains are used for the development of fermented foods.</P>

Acaricidal Activity of Constituents Derived from Peppermint Oil against Tyrophagus putrescentiae

PARK, JUN-HWAN,YANG, JI-YEON,LEE, HOI-SEON International Association for Food Protection 2014 Journal of food protection Vol.77 No.10

<P>The acaricidal activities of peppermint oil and menthol isomers against mites in stored food were evaluated using fumigant and contact bioassays and were compared with the activity of benzyl benzoate as a synthetic acaricide. Based on the 50% lethal dose (LD50) values against Tyrophagus putrescentiae in the fumigant bioassay, menthol (0.96 μg/cm2) was approximately 12.18 times more effective than benzyl benzoate (11.70 μg/cm2), followed by (+)-neomenthol (1.33 μg/cm2), (−)-menthol (1.60 μg/cm2), and (+)-menthol (1.90 μg/cm2). In the filter paper bioassay, menthol (0.55 μg/cm2) was about 15.18 times more active than benzyl benzoate (8.35 μg/cm2), followed by (−)-menthol (0.84 μg/cm2), (+)-menthol (0.92 μg/cm2), and (+)-neomenthol (1.72 μg/cm2). However, (+)-isomenthol did not exhibit any acaricidal activity against T. putrescentiae in the fumigant and filter paper bioassays. These results indicate that peppermint oil and menthol isomers could be effective natural acaricides for managing mites in stored food.</P>

Concentration Method for the Detection of Enteric Viruses from Large Volumes of Foods

CHEONG, SOORYUN,LEE, CHEONGHOON,CHOI, WEON CHEON,LEE, CHAN-HEE,KIM, SANG-JONG International Association for Food Protection 2009 Journal of food protection Vol.72 No.9

<P>Enteric viruses are the major cause of outbreaks of foodborne viral disease worldwide, and vegetables and fruits are considered significant vectors of virus transmission. In this study, we compared viral elution concentration methods in strawberry and lettuce and tested the secondary concentration step for concentrating viruses from large volumes of lettuce samples. Among the tested procedures, the combination of a 0.05 M glycine plus 100 mM Tris elution buffer (pH 9.5) and a polyethylene glycol precipitation concentration was most efficient for the detection of norovirus genogroup II from strawberries (50% of samples) and lettuce (2.9% of samples). The secondary concentration step using ultrafiltration devices could be applied to large lettuce samples without any decrease in detection limit and efficiency, and other cultivable enteric viruses including enteroviruses, adenoviruses, and rotaviruses were recovered from lettuce at efficiencies of 11.4, 9.05, and 11.3%, respectively. This method could be useful for detecting enteric viruses in fresh foods.</P>

Occurrence of Toxigenic Staphylococcus aureus in Ready-to-Eat Food in Korea

OH, SU KYUNG,LEE, NARI,CHO, YOUNG SUN,SHIN, DONG-BIN,CHOI, SOON YOUNG,KOO, MINSEON International Association for Food Protection 2007 Journal of food protection Vol.70 No.5

<P>Toxigenic Staphylococcus aureus contamination in ready-to-eat (RTE) food is a leading cause of foodborne illness in Korea. To monitor food contamination by S. aureus, a total of 3,332 RTE food samples were selected from nationwide wholesale marts between 2003 and 2004 and examined. A total of 285 (8.6%) of the overall samples were contaminated by S. aureus. According to the analysis, 31.6% of the tested cream-cakes, 19.8% of the raw fish, and 19.3% of the rice cakes with filling were contaminated with S. aureus. Forty-seven percent of the strains isolated from the contaminated food were enterotoxigenic S. aureus. The phenotypic result of the strain isolated from food showed that 48% of the strains produced one or more toxins, such as staphylococcal enterotoxins A, B, and C (SEA, SEB, and SEC). At least one SEA was produced by over 90% of the toxigenic strains. Other toxins, such as SEB, SEC, SED, SEA+SEC, and SEC+SED, were each detected. Toxic shock syndrome toxin 1 (TSST-1), a causative agent of toxic shock syndrome, was detected in 13 strains of the toxigenic isolates from the food. As the result of genotyping, 22 strains with a toxin gene that was not detected in the phenotypic analysis were also detected. Sixty-nine percent of the toxigenic strains had at least one sea gene, and the most prevalent genotype was sea+seh (34.4%), followed by sea (18.8%) and sea+seg+sei (15.6%). The tst gene encoding TSST-1 was found in 13 strains (13.5%). The genes (eta and etb) encoding exfoliative toxins A and B were not detected in any of the samples.</P>

Detection of Foreign Bodies in Foods Using Continuous Wave Terahertz Imaging

LEE, YOUNG-KI,CHOI, SUNG-WOOK,HAN, SEONG-TAE,WOO, DEOG HYUN,CHUN, HYANG SOOK International Association for Food Protection 2012 Journal of food protection Vol.75 No.1

<P>Foreign bodies (FBs) in food are health hazards and quality issues for many food manufacturers and enforcement authorities. In this study, continuous wave (CW) terahertz (THz) imaging at 0.2 THz with an output power of 10 mW was compared with X-ray imaging as techniques for inspection of food for FBs. High-density FBs, i.e., aluminum and granite pieces of various sizes, were embedded in a powdered instant noodle product and detected using THz and X-ray imaging. All aluminum and granite pieces (regular hexahedrons with an edge length of 1 to 5 mm) were visualized by both CW THz and X-ray imaging. THz imaging also detected maggots (length = 8 to 22 mm) and crickets (length = 35 and 50 mm), which were embedded in samples as low density FBs. However, not all sizes of maggot pieces embedded in powdered instant noodle were detected with X-ray imaging, although larger crickets (length = 50 mm and thickness = 10 mm) were detected. These results suggest that CW THz imaging has potential for detecting both high-density and low-density FBs embedded in food.</P>

Characterization of Antimicrobial Resistance of Escherichia coli Recovered from Foods of Animal and Fish Origin in Korea

KOO, HYON-JI,WOO, GUN-JO International Association for Food Protection 2012 Journal of food protection Vol.75 No.5

<P>Antimicrobial-resistant Escherichia coli is transferred from food-producing animals to humans through the food chain. We investigated the prevalence of antimicrobial resistance and resistance determinants and characterized the integrons of foodborne E. coli in Korea. In total, 162 E. coli isolates from commercial foods (raw meat, fish, and processed foods) were collected by the National Antimicrobial Resistance Management Program from 2004 to 2006. Susceptibility to 20 antibiotics was tested by disk diffusion, and resistance determinants were detected using PCR and genomic sequence analysis. The isolates were highly resistant to antibiotics commonly used in livestock farming. Resistance to tetracycline (74.7%) was the most frequently observed, followed by streptomycin (71%) and ampicillin (51.2%). Class 1 integrons were detected in 13 isolates (8%), and nine of these integrons were located on conjugative plasmids. None of the isolates produced extended-spectrum β-lactamase. One isolate (0.6%) harbored blaCMY-2, which was located on a conjugative plasmid. Although the qnr gene was not detected, aac(6′)-Ib-cr was present in two isolates (1.2%). This is the first report of aac(6′)-1b-cr in food isolates. Three or four amino acid substitutions at positions 83 and 87 in gyrA and at positions 80 and/or 84 in parC were found in six isolates, representing high resistance to ciprofloxacin (MIC ≥ 16 mg/liter). These results suggest that E. coli isolates carrying resistance genes and integrons are present in the Korean food chain.</P>

Simultaneous Identification of Seven Foodborne Pathogens and Escherichia coli (Pathogenic and Nonpathogenic) Using Capillary Electrophoresis-Based Single-Strand Conformation Polymorphism Coupled with Multiplex PCR

OH, MI-HWA,PAEK, SE-HEE,SHIN, GI WON,KIM, HAE-YEONG,JUNG, GYOO YEOL,OH, SANGSUK International Association for Food Protection 2009 Journal of food protection Vol.72 No.6

<P>The objective of this study was to develop a novel technique for parallel analysis of eight important foodborne microbes using capillary electrophoresis-based single-strand conformation polymorphism (CE-SSCP) coupled with multiplex PCR. Specific primers for multiplex PCR amplification of the 16S rRNA gene were designed, corresponding to eight species of bacteria, including Escherichia coli, Clostridium perfringens, Campylobacter jejuni, Salmonella enterica, Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus, and Bacillus cereus, for the species-specific identification and optimal separation of their PCR products in subsequent analysis by CE-SSCP. Multiplex PCR conditions including annealing temperature, extension time, the number of PCR cycles, and primer concentrations were then optimized for simultaneous detection of all target foodborne bacteria. The diagnostic system using CE-SSCP combined with multiplex PCR developed here can be used for rapid investigation of causative agents of foodborne illness. The simplicity and high sensitivity of the method may lead to improved management of safety and illness related to food.</P>

Perception Gaps on Food Additives among Various Groups in Korea: Food Experts, Teachers, Nutrition Teachers, Nongovernmental Organization Members, and General Consumers

Kang, Hee-Jin,Kim, Suna,Lee, Gunyoung,Lim, Ho Soo,Yun, Sang Soon,Kim, Jeong-Weon International Association for Food Protection 2017 Journal of food protection Vol.80 No.6

<B>ABSTRACT</B><P>The purpose of this study was to determine the perceptions and information needs of food experts, teachers, nutrition teachers, members of nongovernmental organizations, and general consumers concerning food additives. Questions in a survey format included perceptions, information needs, and preferred communication channels. The survey was conducted both off-line and on-line via e-mail and Google Drive in March 2015. The results indicated that most Korean consumers are concerned about the safety of using food additives in processed foods and do not recognize these additives as safe and useful materials as part of a modern diet. We also identified perception gaps among different groups regarding food additives. Nutrition teachers and members of nongovernmental organizations in Korea appeared to have a biased perception of food additives, which may cause general consumers to have a negative perception of food additives. The group of food experts did not have this bias. Governmental institutions must overcome the low confidence levels of various groups as an information provider about food additives. Based on the findings in this study, it will be possible to develop a strategy for risk communication about food additives for each group.</P>

Food Protective and Color Alteration Effects of Acaricidal Aldehydes on Tyrophagus putrescentiae (Schrank)

SUNG, B. K.,LIM, J. H.,LEE, H. S. International Association for Food Protection 2006 Journal of food protection Vol.69 No.7

<P>The activities of benzaldehyde isolated from Prunus persica seeds and of commercially available aldehydes against Tyrophagus putrescentiae (a stored-food mite) adults were examined and compared with those of the synthetic acaricides benzyl benzoate and N,N-diethyl-m-toluamide. On the basis of the 50% lethal dose (LD50), the compound most toxic to T. putrescentiae adults was salicylaldehyde (LD50 of 1.02 μg/cm2) followed by cinnamaldehyde (1.66 μg/cm2), benzaldehyde (4.23 μg/cm2), phthaldialdehyde (5.16 μg/cm2), benzyl benzoate (9.75 μg/cm2), and N,N-diethyl-m-toluamide (16.26 μg/cm2). Benzaldehyde was about 2.3 and 3.8 times more toxic than benzyl benzoate and N,N-diethyl-m-toluamide, respectively, against T. putrescentiae adults. These results indicated that benzaldehyde isolated from P. persica seeds and the three aldehydes (cinnamaldehyde, salicylaldehyde, and phthaldialdehyde) are useful as lead compounds for developing acaricidal agents against T. putrescentiae adults. The color of the T. putrescentiae cuticle was changed by treatment with cinnamaldehyde, salicylaldehyde, and phthaldialdehyde.</P>

Genetic Diversity, Antimicrobial Resistance, and Toxigenic Profiles of Bacillus cereus Strains Isolated from Sunsik

LEE, NARI,SUN, JE MIN,KWON, KYUNG YOON,KIM, HYUN JUNG,KOO, MINSEON,CHUN, HYANG SOOK International Association for Food Protection 2012 Journal of food protection Vol.75 No.2

<P>Bacillus cereus can cause emetic and diarrheal types of food poisoning, but little study has been done on the toxins and toxin-encoding genes of B. cereus strains isolated from Sunsik, a Korean ready-to-eat food prepared from grains, fruits, and vegetables. In this study, 39 unique B. cereus strains were isolated and identified from Sunsik samples, with an average contamination level of 10 to 200 CFU/g. The detection rates of the hblACD, cytK, and bceT genes among all the strains were 48.7, 66.7, and 87.1%, respectively. All 39 B. cereus strains carried nheABC and entFM genes, and 36 strains also had the ces gene, which encodes an emetic toxin. Nonhemolytic enterotoxin and hemolysin BL enterotoxin were produced by 39 and 26 strains, respectively. The strains were separated into 13 profiles based on the presence or absence of toxins and their genes, as determined by antibody tests and PCR analysis. Profile 1 was the largest group, comprising 30.7% (12 of 39) of the B. cereus strains tested; these strains harbored all toxins and their genes. The B. cereus strains were susceptible to most of the antibiotics tested but were highly resistant to β-lactam antibiotics. The repetitive element sequence polymorphism PCR fingerprints of the B. cereus strains were not influenced by the presence of toxin genes or antibiotic resistance profiles. Our results suggest that B. cereus strains from Sunsik could cause either the diarrheal or emetic types of food poisoning because all strains isolated contained at least one toxin and its gene, although the level of B. cereus contamination in Sunsik was low.</P>