• 대한의생명과학회지
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• 제23권4호
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• pp.333-338
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• 2017

This study was performed to assess microbial contamination of Aronia melanocarpa, blueberry, raspberry, and cranberry sold in several markets. We investigated total aerobic bacteria and detected foodborne bacteria by multiplex PCR from Aronia melanocarpa, blueberry, raspberry, and cranberry. Total aerobic bacteria of each sample showed mean 3.54 log CFU/g for Aronia melanocarpa, mean 1.90 log CFU/g for blueberry, and mean 1.40 log CFU/g for raspberry, but not detected in cranberry. Specially, Aronia melanocarpa contained high total aerobic bacteria contamination among various berries and contamination level reached 4.17 log CFU/g in sample 5. To evaluate the effect of distribution conditions, we also investigated total aerobic bacteria of various berries. Total aerobic bacteria showed mean 2.89 log CFU/g for berries in refrigerated distribution and 1.40 log CFU/g in frozen distribution, but not in dry distribution. For assessment of foodborne bacteria contamination, we conducted PCR with multiplex primers of E. coli O157, S. aureus, B. cereus, V. parahaemolyticus, L. monocytogenes, Y. enterocolitica, Salmonella spp., Shigella spp. Among these foodborne bacteria, B. cereus was amplified in Aronia melanocarpa in sample 4 and blueberry in sample 1, 2, 3, and 5. The result of quantitative analysis of B. cereus contamination showed 4.08 log CFU/g of Aronia melanocarpa in sample 4 and higher contamination rate 4.07 log CFU/g of blueberry in sample 3. These results suggest that strict food safety control in harvest and distribution of various berries is necessary to prevent foodborne disease and improve microbiological safety.

• Journal of Dairy Science and Biotechnology
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• 제39권2호
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• pp.68-77
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• 2021

This study aimed to evaluate the effects of antibacterial activity of Tibetan mushroom exopolysaccharide against foodborne pathogenic bacteria Staphylococcus aureus 305, Listeria monocytogenes ATCC19114, Escherichia coli O157:H7 ATCC42894 and Escherichia coli O55. The yield of exopolysaccharide isolated from Tibetan mushroom culture was 620 mg/L. The antibacterial activity of exopolysaccharide against foodborne pathogenic bacteria exhibited 15 mm and 12 mm clear zone against S. aureus 305 and L. monocytogenes ATCC 19114, respectively. However, no clear zone was observed against E. coli O157:H7 ATCC 42894 and E. coli O55. In conclusion, exopolysaccharide isolated from Tibetan mushroom culture have the antibacterial activity only against Gram-positive foodborne pathogenic bacteria.

• Journal of Dairy Science and Biotechnology
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• 제39권3호
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• pp.121-127
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• 2021

Yogurt is produced by bacterial fermentation of milk and contains lactic acid bacteria (LAB), which produce various metabolites such as organic acid, hydrogen peroxide, and bacteriocin. This study aimed to investigate cell-free supernatants (CFS) of LAB isolated from Tibetan yogurt. CFS (TY1, TY2, TY3, TY4, TY5, TY6, and TY7) from selected strains of LAB were co-incubated with four different foodborne pathogenic bacteria, namely E. coli O157:H7, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. Inhibition of foodborne pathogenic bacterial growth was not affected in the presence of CFS (pH 6.5). In contrast, CFS without neutralization completely inhibited the growth of the bacteria. Furthermore, when the concentration of CFS (without neutralization) was changed to 1:4 and 1:8, a difference in inhibition was observed between Gram-positive and Gram-negative bacteria. CFS more effectively inhibited the growth of Gram-negative E. coli O157:H7 and S. Typhimurium than Gram-positive L. monocytogenes and S. aureus. These results suggest that organic acids in LAB may inhibit the growth of foodborne pathogenic bacteria, particularly Gram-negative bacteria.

• 한국식품위생안전성학회지
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• 제35권5호
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• pp.419-429
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• 2020

식품 매개 병원균에 의한 문제는 식품산업뿐 아니라 세계 공공 보건에서도 문제가 된다. 최근 몇 년 간, 발효기술은 식품 내 병원성 미생물의 불활성화 및 이를 조절하기 위한 값 싸고 안전한 방법이라는 것이 밝혀졌다. 유산균 발효는 병원성 세균 및 바이러스에 대해 유의적인 항균효과를 갖는 과학적 증거를 보였다. 유기산, 박테리오신 및 과산화수소와 같은 유산균 대사체는 식품 매개 병원균에 대해 악영향을 미치고 이는 이들의 저해작용으로 이어진다. 이 화합물들은 물리적 결함만을 야기하는 것이 아니라 병원균의 유전자 발현에 대해서도 유의적인 저해 효과를 나타낸다. 게다가, 식품 내 유산균의 존재는 병원균에 대해 영양적인 경쟁을 제공하며 모든 요인이 그 성장을 억제한다. 본 연구는 유산균의 항균력, 분자생물학적 메커니즘 및 식품 매개 병원균의 불활성화를 위한 응용에 대하여 우리의 현 지식을 검토한다.

• Journal of Dairy Science and Biotechnology
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• 제37권3호
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• pp.187-195
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• 2019

Seeds and leaves of Raphanus raphanistrum subsp. sativus (radish) are known to contain "raphanin," which has the potential to inhibit pathogenesis associated with foodborne pathogenic bacteria and fungi. In this study, ethanol extracts from R. raphanistrum subsp. sativus (radish) powder was evaluated for antimicrobial action against 6 different foodborne pathogenic bacteria. The current study demonstrated the potential of R. raphanistrum subsp. sativus (radish) in inhibiting the growth of Salmonella enteritidis 110, Cronobacter sakazakii KCTC 2949, Bacillus cereus ATCC 10876, and Staphylococcus aureus ATCC 6538. However, these antimicrobial action were not observed against Listeria monocytogenes ATCC 51776 and Escherichia coli 23716. Hence, this study indicates that R. raphanistrum subsp. sativus (radish) could be used as a natural biopreservative with antimicrobial effects for improving food safety, and as a functional food in the commercial food industry.

• Journal of Microbiology and Biotechnology
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• 제32권3호
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• pp.355-364
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• 2022

From independent swab samples of the cloaca of indigenous gamecocks (CIG), anus of healthy baby goats (AHG), and vagina of goats (VG) originating from Phitsanulok, Thailand, a total of 263 isolates of lactic acid bacteria (LAB) were collected. Only three isolates, designated C707, G502, and V202, isolated from CIG, AHG, and VG, respectively, exhibited an excellent inhibitory zone diameter against foodborne pathogenic bacteria when evaluated by agar spot test. Isolates C707 and G502 were identified as Enterococcus faecium, whereas V202 was identified as Pediococcus acidilactici, based on 16S rRNA sequence analysis. When foodborne pathogenic bacteria were co-cultured with chosen LAB in mixed BHI-MRS broth at 39℃, their growth was suppressed. These LAB were found to be capable of surviving in simulated stomach conditions. Only the isolate G502 was able to survive in the conditions of simulated intestinal juice. This research suggests that selected LAB could be used as a food/feed supplement to reduce foodborne pathogenic bacteria and improve the safety of animal-based food or feed.

• 급식외식위생학회지
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• 제1권1호
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• pp.27-35
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• 2020

Salt is a common seasoning agent used in various processed foods, especially in kimchi and salted seafood (jeotgal). This study was conducted to investigate the efficacy of salt with antimicrobial substances (acetic acid, garlic extract, carvacrol, nisin, thymol, and their combination (acetic acid+nisin+thymol)) on improvement of antibacterial effects of salt against foodborne pathogens. Salt (10%) was prepared using six different types of 0.2% natural antimicrobial substances. The antibacterial effect of salt combined with natural antimicrobial substances was evaluated against foodborne pathogens using the broth micro-dilution method and growth curve plotted using absorbance measurements. For the five foodborne pathogens, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of salt without antimicrobial substances as control were in the range of 24~>50,000 ㎍/mL and >50,000 ㎍/mL, respectively. Salt with nisin, thymol, or garlic extract showed strong inhibitory effects and their MIC against L. monocytogenes were 49, 12,500, and 24 ㎍/mL, respectively. In particular, salt with nisin showed inhibitory activities against Gram-positive bacteria. However, all the antimicrobial substances were less effective against Gram-negative bacteria such as E. coli O157:H7 and S. Typhimurium than Gram-positive bacteria. These results could be used for the development of salt with natural antimicrobial substances especially targeted against L. monocytogenes. This would enable the lowering of saline concentration while improving the storability of food.

• Food Science and Biotechnology
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• 제15권2호
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• pp.260-263
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• 2006

In this study, we investigated the antimicrobial effect of 14 different herbal petal extracts on various foodborne and food spoilage bacteria. Herbal petal extracts were prepared with 70% ethanol followed by sequential hexane, chloroform, ethyl acetate, n-butanol, and water fractionation. Antimicrobial activity was highest in the ethanol fraction from roselle (Hibiscus sabdariffa L.) petals as determined by the paper disc method. The roselle ethanol extract retarded the growth of food spoilage bacteria in kimbap (rice rolled in dried laver). Foodborne microorganisms (e.g. Bacillus cereus and Clostridium perfringens), on the other hand, were most efficiently inhibited by the ethyl acetate fraction of the roselle petal extract as determined by growth inhibition curves. Our study shows that roselle petals harbor antimicrobial activity against foodborne and food spoilage microorganisms. The critical ingredient is highly enriched in the ethyl acetate fraction of the extract.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.345-352
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• 2023

Antibacterial activity against foodborne bacteria (Bacillus cereus, Staphylococcus aureus, Salmonella Enteritidis) and inhibitory activity against murine norovirus, a human norovirus surrogate, of 28 extracts from plants endemic to Korea were investigated in this study. All plant extracts showed antibacterial activity only against gram-positive bacteria, B. cereus and S. aureus. Extracts from Callistemon speciosus and Nymphaea tetragona showed inhibition zones of 16.54 and 24.35 mm against B. cereus and S. aureus, respectively, presenting the highest antibacterial activities recorded in this study. Among all samples, Ardisia japonica extract at concentrations of 100 and 200 ㎍/mL showed the highest virucidal activities of 96.6 and 100.0%, respectively. Ardisia japonica, Duchesnea indica, Polygonum aviculare, and Geum japonicum extracts showed high antibacterial and virucidal activity simultaneously without Raw 264.7 cell cytotoxicity. These plant extracts may serve as potential antimicrobials to control foodborne infections.

• Journal of Microbiology and Biotechnology
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• 제10권2호
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• pp.227-232
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• 2000

Fresh pine needles were collected and extracted with 95% methanol and the extract was concentrated to determine its antimicrobial activity. The methanol extract had a considerable inhibitory effect on the tested bacteria, such as Esherichia coli 0157;H7, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. The methanol extract of pine needles was further fractionated to chloroform, ethylacetate, butanal, and water fractions. Among these four fractions, the butanol and water fractions, which showed a relatively strong inhibitory effect on all of the tested bacteria, were purified and the minimum ingibitory concentration (MIC) was determined for each microorganism. The MIC raged between 25 mg/ml and 45 mg/ml depending on the microorganism. the purified active fractions were applied to sterilized milk as a model food system to define the antimicrobial effectiveness and it was found that the antimicrobial activities in the water fractions were stronger than those in the butanol fractions.