• Preventive Nutrition and Food Science
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• v.1 no.2
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• pp.196-202
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• 1996

The effect of cooking(boiling, steaming and baking0and drying on the cholesterol content and formation of oxidized cholesterols in quid(Japanese flying squid, Todarodes pacificus) was studied. Cholesterol content of live squid meat varied with the portion sampled, and results from spectrophotometric assay ranged from 263.2mg/1..g(mantle) to 315.8mg/100g(tentacle). The cholesterol levels analyzed by gas chromatography(GC) for squid samples were lower by 7% of total cholesterol for live squid meat and 24% for processed meat than those results by spectrophotometric assay. Cooking resulted in the decrease of the initial total cholesterol content of raw meat from 10%(boiling for 5min.) to 25%(steaming for 5min.) The amounts of cholesterol remaining after baking were 68% for microwave oven samples and 64% for convection oven samples. Drying of raw tissue caused the greater reduction in cholesterol content than cooking but showed no significant difference in samples stored for 6 weeks at 4$^{\circ}C$ and 2$0^{\circ}C$. Raw squid meats contained essentially no oxidized cholesterols, while the 22-hydroxychoesterol was detected in frozen meats. The additional oxidized cholesterols as cholestane-triol was indentified with 22-hydroxycholesterols in cooked samples. Sun dried meat stored at 4一 and 2$0^{\circ}C$ for 6 weeks had the three kinds of oxidized cholesterols such as 22-hydroxycholesterol, cholesta-3,5-dien-7-one and cholestane-triol.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2003.06a
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• pp.1-14
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• 2003

Lipid oxidation is one of the most important non-microbial causes of meat quality deterioration. However, there have been different/conflicting views concerning the primary catalysts of lipid oxidation in meat. This presentation provides brief overviews of lipid oxidation mechanism in general and catalysis of lipid oxidation in meat, and then focuses on inter-species differences in lipid oxidation potential, using results from our studies on meats (beef, pork and chicken) at retail and the respective meats of uniform postmortem history. The inter-species differences have highlighted the relative roles of meat pigment (myoglobin) content, catalase activity, and the concentration of oxidation substrates (particularly polyunsaturated fatty acids) in determining the lipid oxidation potential of raw meat versus cooked meat.

• Journal of the Korean Society of Food Culture
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• v.17 no.4
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• pp.465-472
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• 2002

The effect of cooking(boiling, steaming and baking) and drying on the cholesterol content and formation of oxidized cholesterols and acid value in squid(Japanese flying squid, Todarodes pacificus) was studied. Cholesterol content of live squid meat varied with the portion sampled. The data from spectophotometric assay ranged from 263.2 mg/100g(mantle) to 315.8 mg/100g(tentacle). The cholesterol levels found for squid samples analyzed by gas chromatography(GC) were lower by 7% of total cholesterol for live squid meat and 24% for processed meat than those results by spectrophotometric assay. Cooking resulted some decrease in the initial total cholesterol content of raw meat from 10%(boiling for 5 min.) to 25%(steaming for 5 min.). The amounts of cholesterol remaining after baking were 68% for microwave oven samples and 64% for convection oven samples. Drying of raw tissue caused the greater reduction in cholesterol content than cooking but brought about no significant difference in samples stored for 6 weeks at $4^{\circ}C\;and\;20^{\circ}C$. Raw squid meats contained essentially no oxidized cholesterols, while the 22-hydroxychoesterol was detected in frozen meats. The additional oxidized cholesterols as cholestane-triol was indentified with 22-hydroxycholesterol in cooked samples. Sun dried meat stored at $4^{\circ}C\;and\;20^{\circ}C$ for 6 weeks had the three kinds of oxidized cholesterols such as 22-hydroxycholesterol, cholesta-3,5-dien-7-one and cholestane-triol. For the boiled and steamed squids, 10% higher acid value and 5% higher acid value respectively were observed but oven cooked samples resulted in a 50% higher acid value than raw samples. Squids had a 45% higher acid value than raw one during sundrying and presrevation at $20^{\circ}C$ but there was not a severe difference of acid value between $4^{\circ}C\;and\;20^{\circ}C$ stored samples.

• Food Science of Animal Resources
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• v.35 no.5
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• pp.669-673
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• 2015

The aims of this study were to investigate the occurrence of Listeria species in turkey meats and to check the antimicrobial susceptibility of the isolated strains. Hundred and fifteen raw turkey meat samples were randomly collected from the supermarkets, butchers and restaurants. Strain isolation and identification were made according to the ISO11290-1 method. Antimicrobial susceptibility was determined by the standard disc diffusion method. A total of 47 Listeria spp. were isolated from 115 (40.9%) raw turkey meat samples. The isolates were distributed between L. monocytogenes (25.53%), L. innocua (34.04%), L. grayi (31.91%) and L. welshimeri (8.51%). A total of 55.3 % of Listeria spp. isolates were multi-resistant to at least 3 of the antimicrobial agent tested. The level of multi-resistance was higher in L. monocytogenes strains (66.7%) than in L. innocua (62.5%) and L. grayi (53.3%). Listeria spp. isolates were highly resistant to ampicillin, cephalothin, penicillin, meticillin, oxacillin, and trimethoprime-sulfamethoxazole. The isolates particularly L. monocytogenes are increasingly resistant to one or more antibiotics and may represent a potential risk for public health because these antibiotics are common used in treatment of listeriosis. The correct and controlled use of antibiotics in veterinary medicine is important to the emergence of resistant strains.

• Korean Journal of Agricultural Science
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• v.42 no.2
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• pp.131-139
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• 2015

This study investigated the quality properties of smoked breast meats produced by fresh and frozen-thawed duck meat. Each thirty breast meats from fresh and frozen-thawed duck carcass was used for this study. The yield of smoked breast meat was measured right after curing and smoking of raw duck breast meat. And, the number of total aerobic bacteria, color, texture, and sensory property of vacuum-packaged smoked breast meats were evaluated during storage at $4^{\circ}C$ for 28 days. No significant difference was found in yield between smoked breast meats produced by fresh and thawed duck meats (p>0.05). The number of total aerobic bacteria and color of smoked breast meat produced by thawed duck meat were not significantly different compared with those by fresh one throughout storage period (p>0.05). The all texture properties were not significantly different between smoked breast meats produced by fresh and thawed duck meats by 14 days of storage (p>0.05). However, on day 21 and 28, the hardness and gumminess of smoked breast meat produced by fresh duck meat were significantly higher than those by thawed one (p<0.05). In sensorial property, smoked breast meat produced by thawed duck meat received significantly high scores in color, juiciness, and tenderness on days 0, 14, and 28 and in flavor and overall acceptance on days 0 and 14 compared with those by fresh one (p<0.05). Therefore, we concluded that the use of thawed duck meat for producing smoked duck meat product may be not worse than the use of fresh duck meat in quality of smoked duck meat product. In addition, the use of thawed duck meat may be better in sensorial quality of smoked duck meat product than that of fresh one.

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

• Food Science of Animal Resources
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• v.33 no.1
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• pp.133-138
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• 2013

In this study, a total of 256 samples of retail raw meats (beef, pork and chicken) and sashimi were investigated for the presence of Enterococcus faecalis and Enterococcus faecium. We isolated a total of 117 E. faecalis and E. faecium from the samples, with contamination rates ranging from 18.8% for sashimi samples to 68.8% of chicken samples. E. faecalis was the predominant species recovered from all of the retail raw meats beef (42.2%), pork (42.2%), chicken (65.6%) and sashimi (12.5%). Among 117 isolates, 61 isolates (52.1%) were resistant to tetracycline, 32 isolates (27.4%) were resistant to erythromycin, 23 isolates (19.7%) were resistant to chloramphenicol, 16 isolates (13.7%) were resistant to ripampin, 10 isolates (8.5%) were resistant to gentamycin, 9 isolates (7.7%) were resistant to ciprofloxacin and 1 isolate (0.9%) was resistant to ampicillin and penicillin G. No resistance to amoxicillin + clavulanic acid and vancomycin was observed. Although no strain was resistant to vancomycin, the vanB gene was observed in 9 of 117 of Enterococcus (7.7%) demonstrating potential risk of vancomycin-resistant Enterococcus (VRE). Our results indicate that E. faecalis and E. faecium were highly prevalent in retail raw meats, but most strains were sensitive to tested antibiotics.

• Journal of Food Hygiene and Safety
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• v.35 no.2
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• pp.170-176
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• 2020

We investigated the pH, volatile basic nitrogen (VBN), microbial changes and dominant microbes in raw beef, wet-aging beef, and dry-aging beef after the meat had been stored in a refrigerator. The count of mesophilic bacteria was 3.3-3.9 log CFU/g in raw beef and dry-aging beef, and 5.4 log CFU/g in wet-aging meat. After 18 days of refrigeration, the mesophilic bacterial count in raw and aging beef increased to 6.1-6.4 log CFU/g. In wet-aging beef, the number of lactic acid bacteria increased from 4.5 log CFU/g to 6.0 log CFU/g at refrigeration temperature. However, lactic acid bacteria were not detected in dry aging beef. Major foodborne pathogens such as Salmonella spp, Listeria monocytogenes, and Escherichia coli (EHEC) were not detected. Based on the legal standard for mesophilic bacteria count, the estimated shelf-life of aged beef was less than 12 days and the average VBN was 15 mg%. The dominant microorganisms varied between the different types of meat. In raw meat, Staphylococcus saprophyticus was the dominant microorganism, and as the VBN increased, Carnobacterium divergens dominated. In wet-aging beef, Carnobacterium divergens dominated during the initial days of refrigeration after which the number of Lactobacillus sakei increased. Dermacoccus nishinomiyaensis was initially the dominant microbe in dry-aging beef, after which Pseudomonas fragi dominated. In addition to the role of specific bacteria in the early stage of decay, it is thought that microorganisms can be utilized for safe distribution and storage of matured meats by conducting research on changes in rot, fragrance analysis, and changes of ingredients in matured meats.

• Environmental Analysis Health and Toxicology
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• v.22 no.4
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• pp.313-320
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• 2007

본 연구는 인간의 건강과 식품의 오염을 예방하기 위한 유용한 자료를 얻기 위하여 육류(소고기, 닭고기, 돼지고기)로부터 분리된 staphylococci를 가지고 한국에서 광범위하게 사용되는 6가지 항생제와 daptomycin, linezolid, quinupristin/dalfopristin and tigecycline과 같은 4가지의 신항생제에 대한 항생제 감수성 시험을 수행하였다. 이에 더하여 육류의 세균 오염실태를 조사하기 위하여 총 세균수와 대장균수를 측정하였다. 그 결과 147개의 육류 샘플 중 48%의 샘플에서 일반세균수의 기준에 부적합한 결과가 나타났으며, 대장균수에 대해서는 31%의 샘플에서 기준에 부적합한 결과가 나타났다. 또한 육류의 91%에서 stapylococci가 검출되었으며 이들 staphylococci는 Coagulase Negative Staphylococci (CNS)와 S. aureus로 동정되었다. 분리된 staphylococci의 5.4%가 methicillin (oxacillin)에 내성을 나타내었고, 특히 mupirocin ($MIC_{90},\;>\;12\;{\mu}g/mL$) gentamicin ($MIC_{90},\;64\;{\mu}g/mL$)에 높은 내성을 나타내었다. 그러나 신항생제에 대해서는 methicillin 내성 staphylococci를 포함한 모든 staphylococci 분리균주가 높은 감수성을 나타내었다. 결론적으로 본 연구의 결과들은 육류가 소비자들의 건강에 중요한 위험요소로 작용할 수 있음을 보여주고 있다.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1307-1314
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• 2022

In this study, we sought to investigate the various characteristics of Salmonella spp. isolated from raw chicken meats available in Korean markets. The data collected, such as food source of isolation, sampling information, serotype, virulence, and genetic profile including sequence type, were registered in the database for further comparative analysis of the strains isolated from the traceback investigation samples. To characterize serotype, virulence and gene sequences, we examined 113 domestically distributed chicken meat samples for contamination with Salmonella spp. Phylogenetic analysis was conducted on 24 strains (21.2%) of Salmonella isolated from 113 commercially available chicken meats and by-products, using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Serotyping of the isolated Salmonella spp. revealed S. Enteritidis in 11 strains (45.8%), S. Virchow in 6 strains (25%), S. Montevideo in 2 strains (8.3%), S. Bsilla in 2 strains (8.3%), S. Bareilly in 1 strain (4.2%), S. Dessau in 1 strain (4.2%), and S. Albany in 1 strain (4.2%). The genetic correlation indicated that 24 isolated strains were classified into 18 clusters with a genetic similarity of 64.4-100% between them. Eleven isolated S. Enteritidis strains were classified into 9 genotypes with a sequence identity of 74.4%, whereas the most distantly related S. Virchow was divided into five genotypes with 85.9% identity. Here, the MLST analysis indicated that the major Sequence Type (ST) of the Salmonella spp. isolated from domestic chicken sold in Chungcheong Province belongs to the ST 11 and 16, which differs from the genotype of Salmonella isolated from imported chicken. The differential sequence characteristics can be a genetic marker for identifying causative bacteria for epidemiological investigations of food poisoning.