• Korean Journal of Plant Resources
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• v.21 no.5
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• pp.352-356
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• 2008

This study was performed to investigate the antimicrobial effects of Origanum majorana L. ethanol extract against food-borne pathogens. The antimicrobial activity of Origanum majorana L. extract was determined using a paper disc method. The extract exhibited growth inhibiting activities in a concentration dependent manner on 10 species microorganisms. The extract of Origanum majorana L. showed the highest antimicrobial activity against Salmonella enteritidis. The growth inhibitory effects of Origanum majorana L. extract on food poisoning microorganisms were determined against Salmonella typhimurium and Listeria monocytogenes, gram negative and positive bacteria, respectively. The extract of Origanum majorana L. had strong antimicrobial activity against Salmonella typhimurium and Listeria monocytogenes at the concentration of $700 mg{\cdot}L^{-1}$. At this concentration, the extract of Origanum majorana L. inhibited the growth of Salmonella typhimurium and Listeria monocytogenes up to 60 and 36 hours, respectively. The results in the present study demonstrate antimicrobial effects of Origanum majorana L. ethanol extract against food-borne pathogens, suggesting that Origanum majorana L. could be an effective natural antibacterial agent in food.

• Journal of Food Hygiene and Safety
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• v.32 no.6
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• pp.500-506
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• 2017

Kimchi cabbage is one of the four major vegetable crops in Korea. The total annual production of kimchi cabbage, the main material of kimchi, was 20,559 tons in 2015. Kimchi cabbage is one of the majer crops produced by farmers which accounts for about 80% of the total leaf vegetable production in Korea. As the consumption of environmental-friendly agricultural products increases, food safety is one of the major public health concerns. We analyzed the biological hazards of kimchi cabbage produced by two types of cultivation methos such as organic farming and conventional farming using various culture media and microscopy. A total of 432 samples were analysed for presence of sanitary indicator microorganisms (aerobic plate count, coliform count, yeast & mold) and food-borne pathogens (Staphylococcus aureus, environmental Listeria, Bacillus cereus). The population of sanitary indicating microorganisms and food borne pathogens was under 5 Log CFU/g in all tested samples. The results of total microorganism numbers of leaf surface showed a positive correlation to those of soil samples. Additionally, we examined chemical factors such as pesticide residues and heavy metals in soil samples. All tested samples did not shown contamination levels higher than the standard limit.

• Food Science and Industry
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• v.52 no.3
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• pp.220-228
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• 2019

Rapid development of next-generation sequencing (NGS) technology is available to study microbes in genomic level. This NGS has been widely used in DNA/RNA sequencing for genome sequencing, metagenomics, and transcriptomics. The food microbiology area could be categorized into three groups. Food microbes including probiotics and food-borne pathogens are studied in genomic level using NGS for microbial genomics. While food fermentation or food spoilage are more complicated, their genomic study needs to be done with metagenomics using NGS for compositional analysis. Furthermore, because microbial response in food environments are also important to understand their roles in food fermentation or spoilage, pattern analysis of RNA expression in the specific food microbe is conducted using RNA-Seq. These microbial genomics, metagenomics, and transcriptomics for food fermentation and spoilage would extend our knowledge on effective utilization of fermenting bacteria for health promotion as well as efficient control of food-borne pathogens for food safety.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1106-1111
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• 2004

This study was performed to investigate the antimicrobial effect of the Indigofera kirilowii extracts against food-borne pathogens. The Indigofera kirilowii was extracted with methanol at room temperature, and fractionation of the methanol extract from Indigofera kirilowii was carried out by using petroleum ether, chloroform, ethyl acetate, and methanol, respectively. The antimicrobial activity of the Indigofera kirilowii extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The ethyl acetate extract of Indigo/era kirilowii showed the highest antimicrobial activity against Staphylococcus aureus and Shigella dysenteriae. The water extract of Indigofera kirilowii showed relatively low antimicrobial activity against microorganisms used in this experiment. The synergistic effect has been found in combined extracts of Indigofera kirilowii and Pulsatilla koreana as compared to each extract alone. The growth inhibition curve was determined using ethyl acetate extracts of Indigofera kirilowii against S. aureus and S. dysenteriae. The ethyl acetate extract of Indigofera kirilowii showed strong antimicrobial activity against S. aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate extract from Indigofera kirilowii retarded the growth of S. aureus more than 24 hours and S. dysenteriae up to 48 hours. This study showed the possibility of using ethyl acetate extract of Indigofera kirilowii as a material of food preservative.

• Microbiology and Biotechnology Letters
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• v.33 no.2
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• pp.130-135
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• 2005

To investigate the antimicrobial effect of the Patrinia scabiosaefolia extracts against food-borne pathogens, we extracted the P. scabiosaefolia with methanol at room temperature and the fractionation of the methanol extracts was carried out by using petroleum ether, chloroform, ethyl acetate, and methanol, respectively. The antimicrobial activity of the P. scabiosaefolia extracts was determined by using a paper disc method against food-borne pathogens and food spoilage bacteria. The ethyl acetate extracts of P. scabiosaefolia showed the highest antimicrobial activity against Escherichia coli and Shigella sonnei. Synergistic effect in inhibition was observed when P. scabiosaefolia extract was mixed Forsythiae fructus extract as compared to each extracts alone. Finally, the growth inhibition curves were determined by using ethyl acetate extracts of P. scabiosaefolia against Staphylococcus epidermidis and Shigella sonnei. The ethyl acetate extract of P. scabiosaefolia had strong antimicrobial activity against S. sonnei at the concentration of 4,000 ppm. At this concentration, the growth of S. Sonnei was retarded more than 72 hours and up to 48 hours for S. epidermidis. These results suggest that the ethyl acetate extracts of P. scabiosaefolia can be used for the efficient material against the growth of S. epidermidis and S. sonnei.

• Applied Biological Chemistry
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• v.51 no.4
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• pp.251-257
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• 2008

Different types of milk products, such as kwacha golla, mawa, cheese, curd, and chocolate are popular in Bangladesh. However, the microbiological safety of these products is poorly understood. This study was performed to assess the microbiological quality of kwacha golla, a local milk product. Kwacha golla samples were collected from ten different areas of Rajshahi and Kushtia regions, and the quality of the each sample was assessed using various parameters including standard plate count, total coliform, fecal coliform, total fungi, and spore-forming bacteria, as well as food-borne microorganisms. Out of 300 samples, total coliform was detected at 56.66% (n= 300), exceeding the minimum allowable limit of 36.66%. Similarly, experiments were carried out with fungi and food-borne pathogens including Escherichia coli, Listeria monocytogenes, Salmonella sp., and Staphylococcus aureus. Results revealed 85.33, 53, and 49.33% of the samples were contaminated by fungi, E. coli, and L. monocytogenes, respectively. However, all samples showed no contaminations of Salmonella sp. and Staphylococcus sp. Therefore, this study could be helpful to the people of Bangladesh by providing information on the possibility of a major health problem caused by the consumption of kwacha golla.

• Journal of Food Hygiene and Safety
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• v.38 no.4
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• pp.217-227
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• 2023

The consumption of ready-to-eat side dishes is rapidly growing in South Korea. These foods are particularly vulnerable to microbiological contamination as they are often cooked without any treatment, such as heating or stored at room temperature after cooking. Hence, in 2022, we analyzed the ready-to-eat side dishes sold in Gyeongsangnam-do, South Korea for microbiological contamination. We collected 100 samples from supermarkets in 7 cities, and then examined them for presence of food-borne pathogens and sanitary indicator bacteria. In the analysis of the food-borne pathogens, Bacillus cereus and Clostridium perfringens were isolated from 51 samples (51.0%) and 3 samples (3.0%), respectively. However, both quantitatively met the Korean Food Standards Codex. Genes of five different enterotoxins and one emetic toxin were analyzed from the 51 isolated B. cereus strains. We detected enterotoxin entFM (100.0%), nheA (94.1%), hblC (58.8%), cytK (56.9%), and bceT (41.2%) in 51 isolates, and emetic toxin gene, CER, in only one (2.0%) isolate. We did not detect C. perfringens toxin gene (cpe) that causes food poisoning in any one of the three C. perfringens isolates. In the case of sanitary indicator bacteria, Kimchi had the highest levels of total aerobic bacteria and coliforms, followed by Saengchae, Jeotgal, Jeolim, Namul, and Jorim, respectively. We counted total aerobic bacteria at two different storage temperatures (4℃ and 20℃) to determine the effect of storage temperature. When stored at 20℃, total aerobic bacteria count increased in most of the ready-to-eat side dishes, except for Jeotgal. This result conclusively shows the need for refrigerating the ready-to-eat side dishes after purchase. Further research is needed to assess the risk and safety of the ready-to-eat side dishes available in the market and determine appropriate safety management practices.

• Journal of Nutrition and Health
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• v.38 no.2
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• pp.112-116
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• 2005

This study was performed to investigate the antimicrobial effect of the Agrimonia pilosa Ledeb. extracts against food-borne pathogens. First, the Agrimonia pilosa Ledeb. was extracted with methanol at room temperatures, and fractionation of the methanol extracts from Agrimonia pilosa Ledeb. was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol respectively. The antimicrobial activity of the Agrimonia pilosa Ledeb. extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The petroleum ether extracts of Agrimonia pilosa Ledeb. showed the highest antimicrobial activity against Pseudomonas aeruginosa. The synergistic effect has been found in combined extracts of Agrimonia pilosa Ledeb. and Perillae folium as compared to each extracts alone. Finally, the growth inhibition curve was determined using ethyl acetate extracts of Agrimonia pilosa Ledeb. against Bacillus Cereus and Salmonella Enteritidis. The petroleum ether extract of Agrimonia pilosa Ledeb. showed strong antimicrobial activity against Bacillus Cereus at the concentration of 4,000 ppm. The 4,000 ppm of petroleum ether extract from Agrimonia pilosa Ledeb. retarded the growth of Bacillus Cereus more than 24 hours and Salmonella Enteritidis up to 36 hours. The petroleum ether extracts of Agrimonia pilosa Ledeb. has been shown the antimicrobial effect against Bacillus Cereus and Salmonella Enteritidis. (Korean J Nutrition 38(2): 112～116, 2005)

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.107-112
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• 2005

This study was performed to investigate the antimicrobial effect of the Hedyotis diffusa extracts against food-borne pathogens. First, the Hedyotis diffusa was extracted with methanol at room temperature and the fractionation of the methanol extracts was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol respectively. The antimicrobial activity of the Hedyotis diffusa extracts was determined by using a paper disc method against food-borne pathogens and food spoilage bacteria. The methanol extracts of Hedyotis diffusa showed the highest antimicrobial activity against Staphylococcus aureus and Shigella flexneri. Synergistic effect in inhibition was observed when Hedyotis diffusa extract was mixed Sophora subprostrata extract as compared to each extracts alone. Finally, the growth inhibition curves were determined by using ethyl acetate extracts of Hedyotis diffusa against Staphylococcus aureus and Salmonella Typhimurium. The methanol extract of Hedyotis diffusa had strong antimicrobial activity against Staphylococcus aureus at the concentration of 4,000 ppm. At this concentration, the growth of Staphylococcus aureus was retarded more than 36 hours and up to 24 hours for Salmonella Typhimurium. In conclusion, the methanol extracts of Hedyotis diffusa inhibit efficiently Staphylococcus aureus and Salmonella Typhimurium.

• Journal of Food Hygiene and Safety
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• v.31 no.6
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• pp.406-413
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• 2016

This study was performed to evaluate and establish a sample preparation method for the detection of food-borne pathogens in animal origin foods. Ham, yogurt, and Korean beef inoculated with Escherichia coli O157:H7, Staphylococcus aureus, and Salmonella Typhimurium, were tested for the effects of diluent composition, processing time, and proportion of diluent to sample. The diluents used were peptone water (PW), Saline solution (SS), Butterfield's phosphate buffered dilution water (BPD), and Buffered peptone water (BPW). The processing time periods considered for the samples were 30, 60, 90, 120, and 300 sec, and the proportions of diluent to samples tested were 1:2, 1:4, 1:9, and 1:19. Yogurt and beef showed the highest number of bacteria when treated with BPW (p < 0.05). However, ham showed no significant difference between the treatments with four different diluents. Optimum proportions of diluent to ham, yogurt, and beef were 1:9, 1:2, and 1:4, respectively. The processing time of 120 sec was chosen as optimum, because it showed the best recovery rate in all sample types. In this manner, detection of food-borne bacteria with the selected optimal conditions was indicated by a recovery rate of more than 85%. These data suggest that an appropriate diluent composition and diluent volume should be used depending on the type of sample, which would thereby increase the accuracy of detecting food-borne bacteria in animal origin foods.