훈제 및 생연어에서 Listeria monocytogenes의 정량적 미생물 위해성 평가

송기영,양소영,이은우,윤기선 한국식품위생안전성학회 2021 한국식품위생안전성학회지 Vol.36 No.2

본 연구에서는 훈제연어와 연어회 및 샐러드 등에 많이 활용되는 생연어 섭취에 따른 L. monocytogenes 에 의한 식중독 발생 리스크를 비교하기 위해 정량적 미생물 위해성 평가를 수행하였다. 연구 결과 하루에 1회 훈제연어와 생연 어 섭취로 L. monocytogenes로 인한 식중독 발생 가능성은 취약계층의 경우 1.02×10-7, 6.99×10-13이며, 일반계층에서는 2.27×10-9, 1.55×10-14으로 나타나 취약계층에서 식중독 발생 가능성은 훈제연어의 경우 100배, 생연어의 경우 10배로 증 가하는 것으로 확인되었다. 또한 생연어가 훈제연어보다 식중독 발생 가능성이 낮은 것으로 확인되었는데, 이는 생연어는 짧은 유통기한 때문에 냉장온도에서 최고농도로 증가할 수 있는 가능성이 매우 낮기 때문인 것으로 나타났다. 그러나 L. monocytogenes 최소 감염량이 102-103 cells로 매우 낮은 것을 고려할 때 임신부, 고령층과 같은 취약계층에 대한 식품안전 교육이 더욱 필요할 것으로 사료된다. 훈제연어에서는 염지, 훈연공정 때문에 4oC, 10oC 냉장보관 초기에는 L. monocytogenes의 성장이 다소 저해되었으나 각각 6.4일, 2.7일 후 다시 증식하는 것으로 확인되었다. 결론적으로 훈제연어에서 L. monocytogenes 오염수준이 높고 냉장 보관온도가 남용(10oC) 되었을 때 냉장유통 기간인 2주 동안에도 최고 농도로 성장해 식중독 발생 리스크가 높아질 수 있다. 따라서 훈제연어의 공정과정에서 L. monocytogenes 가 오염되지 않도록 철저한 위생관리가 필요하며 온·오프라인 유통환경관리에 대한 재점검이 필요할 것으로 사료된다. Salmon is recognized as a health-promoting functional food due to its high content of unsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and thus demand has increased globally. This study compared the risk of Listeria monocytogenes between smoked and raw salmon samples from online and offline markets. L. monocytogenes was in two out of 375 smoked salmon samples, while no L. monocytogenes was detected in 350 samples of raw salmons. L. monocytogenes began to grow after 3 and 6 d storage at 4oC in both raw and smoked salmon, respectively. The contamination level of L. monocytogenes increased in both smoked and raw salmon from the market to home. The lag time of L. monocytogenes growing in smoked salmons was longer than that in raw salmons, but no significant difference in the growth rates was observed between the two products. Although the growth potential of L. monocytogenes was higher in raw than smoked salmon, the longer shelf life of smoked salmon at refrigerated temperature increased the risk of consuming smoked salmon. The probability risk of listeriosis due to smoked salmon consumption (2.27×10-9) was higher than that of raw salmon (1.55×10-14) for the general population. However, the risk of foodborne illness for the susceptible population increased 10 and 100 times with both smoked and raw salmon consumption.

증균배지에서의 Listeria Interspecies의 경쟁생육 비교

이다연,조용선 한국식품위생안전성학회 2018 한국식품위생안전성학회지 Vol.33 No.1

Monitoring of Listeria monocytogenes, the causative agent of listeriosis, in food is inportant for public health. The Korean Food Standards Codex has adopted a ‘zero-tolerance’ policy for L. monocytogenes. The standard detection method of L. monocytogenes is based on enrichment. Thus, proper enrichment methods need to be instituted to ensure quality control of the detection procedures. In this study, the growth of L. monocytogenes and Listeria innocua as a mixed culture in Listeria enrichment broth (LEB) was monitored during artificial contamination of enrichment culture. We confirmed competitive growth or interspecies inhibitory activity of L. monocytogenes and L. innocua. Interspecies growth differences and the inhibitory activity of different inoculation and mixtures L. innocua against L. monocytogenes were examined. The concentration of L. monocytogenes must be 2.0 log CFU/mL or more than L. innocua to grow better than L. innocua. It is known that Listeria spp. and L. monocytogenes show growth difference during LEB, resulting in the risk of false-negative results. The inhibition of L. monocytogenes by L. innocua was always observed when present at lower concentrations. However, it was confirmed that L. innocua suppressed when L. monocytogenes was present at a higher concentration. Therefore if a mixture of Listeria spp. is present, detecting L. monocytogenes is difficult. Thus, a new enrichment broth to improve the detection rate of L. monocytogenes is needed.

오미자(Schizandra chinensis)의 구성 유기산이 L. monocytogenes의 생육에 미치는 영향

이신호,임용숙 경산대학교 생명자원개발연구소 1999 생명자원과 산업 Vol.3 No.-

오미자의 구성 유기산은 L. monocytogenes scott A, L. monocytogenes Brie Ⅰ 및 L. monocytogenes ATCC 19111에 대해서 항균 효과를 나타내었다. 오미자의 주된 유기산인 fumaric acid, malic acid, citric acid 및 itaconic acid와 같은 0.1% 수준의 유기산에 의해서 L. monocytogenes의 성장이 억제되었다. 오미자의 구성 유기산 중 fumaric acid가 가장 효과가 우수하였다. 오미자의 구성 유기산 중 가장 효과가 뛰어난 fumaric acid에 의한 미생물 형태 변화를 살펴본 결과 대조구는 그 모양이 smooth한 반면에 처리구는 그 모양이 불규칙하고 부푼 형태학적인 변화를 보였다. The organic acid of Schizandra chinensis showed antimicrobial activty against three strains of L. monocytogenes scott A, L. monocytogenes Brie Ⅰ and L. monocytogenes ATCC 19111. The growth of L. monocytogenes was inhibited by 0.1% of various organic acids such as fumaric acid malic acid, citric acid, succinic acid and itaconic acid which were major components of Schizandra chinensis. The fumaric acid of Schizandra chinensis showed more strong inhibitory activity activity than the other acids of Schizandra chinensis. Cell surface of L. monocytogenes Scott A was irregular, swell and disrupted in fumaric acid of Schizandra chinensis treated cell but smooth in normal cell.

Deciphering the Biodiversity of Listeria monocytogenes Lineage III Strains by Polyphasic Approaches

Hanxin Zhao,Jianshun Chen,Chun Fang,Ye Xia,Changyong Cheng,Lingli Jiang,Weihuan Fang 한국미생물학회 2011 The journal of microbiology Vol.49 No.5

Listeria monocytogenes is a foodborne pathogen of humans and animals. The majority of human listeriosis cases are caused by strains of lineages I and II, while lineage III strains are rare and seldom implicated in human listeriosis. We revealed by 16S rRNA sequencing the special evolutionary status of L. monocytogenes lineage III, which falls between lineages I and II strains of L. monocytogenes and the non-pathogenic species L. innocua and L. marthii in the dendrogram. Thirteen lineage III strains were then characterized by polyphasic approaches. Biochemical reactions demonstrated 8 biotypes, internalin profiling identified 10 internalin types clustered in 4 groups, and multilocus sequence typing differentiated 12 sequence types. These typing schemes show that lineage III strains represent the most diverse population of L. monocytogenes, and comprise at least four subpopulations IIIA-1, IIIA-2, IIIB, and IIIC. The in vitro and in vivo virulence assessments showed that two lineage IIIA-2 strains had reduced pathogenicity, while the other lineage III strains had comparable virulence to lineages I and II. The IIIB strains are phylogenetically distinct from other subpopulations, providing additional evidence that this sublineage represents a novel lineage. The two biochemical reactions L-rhamnose and L-lactate alkalinization, and 10 internalins were identified as potential markers for lineage III subpopulations. This study provides new insights into the biodiversity and population structure of lineage III strains, which are important for understanding the evolution of the L. monocytogenes-L. innocua clade.

The Effects of Sodium Chloride on the Physiological Characteristics of Listeria monocytogenes

Choi, Kyoung-Hee,Yoon, Yohan Korean Society for Food Science of Animal Resource 2013 한국축산식품학회지 Vol.33 No.3

Sodium chloride is used to improve various properties of processed meat products, e.g., taste, preservation, water binding capacity, texture, meat batter viscosity, safety, and flavor; however, many studies have shown that sodium chloride increases the resistance of many foodborne pathogens to heat and acid. Listeria monocytogenes has been isolated from various readyto- eat (RTE) meat and dairy products formulated with sodium chloride; therefore, the objective of this paper was to review the effects of sodium chloride on the physiological characteristics of L. monocytogenes. The exposure of L. monocytogenes to sodium chloride may increase biofilm formation on foods or food contact surfaces, virulence gene transcription, invasion of Caco-2 cells, and bacteriocin production, depending on L. monocytogenes strain and serotype as well as sodium chloride concentration. When L. monocytogenes cells were exposed to sodium chloride, their resistance to UV-C irradiation and freezing temperatures increased, but sodium chloride had no effect on their resistance to gamma irradiation. The morphological properties of L. monocytogenes, especially cell elongation and filament formation, also change in response to sodium chloride. These findings indicate that sodium chloride affects various physiological responses of L. monocytogenes and thus, the effect of sodium chloride on L. monocytogenes in RTE meat and dairy products needs to be considered with respect to food safety. Moreover, further studies of microbial risk assessment should be conducted to suggest an appropriate sodium chloride concentration in animal origin foods.

The Effects of Sodium Chloride on the Physiological Characteristics of Listeria monocytogenes

최경희,윤요한 한국축산식품학회 2013 한국축산식품학회지 Vol.33 No.3

Sodium chloride is used to improve various properties of processed meat products, e.g., taste, preservation, water binding capacity, texture, meat batter viscosity, safety, and flavor; however, many studies have shown that sodium chloride increases the resistance of many foodborne pathogens to heat and acid. Listeria monocytogenes has been isolated from various ready-to-eat (RTE) meat and dairy products formulated with sodium chloride; therefore, the objective of this paper was to review the effects of sodium chloride on the physiological characteristics of L. monocytogenes. The exposure of L. monocytogenes to sodium chloride may increase biofilm formation on foods or food contact surfaces, virulence gene transcription, invasion of Caco-2 cells, and bacteriocin production, depending on L. monocytogenes strain and serotype as well as sodium chloride concentration. When L. monocytogenes cells were exposed to sodium chloride, their resistance to UV-C irradiation and freezing temperatures increased, but sodium chloride had no effect on their resistance to gamma irradiation. The morpho-logical properties of L. monocytogenes, especially cell elongation and filament formation, also change in response to sodium chloride. These findings indicate that sodium chloride affects various physiological responses of L. monocytogenes and thus, the effect of sodium chloride on L. monocytogenes in RTE meat and dairy products needs to be considered with respect to food safety. Moreover, further studies of microbial risk assessment should be conducted to suggest an appropriate sodium chloride concentration in animal origin foods.

The Effects of Sodium Chloride on the Physiological Characteristics of Listeria monocytogenes

Kyoung Hee Choi,Yo Han Yoon 한국축산식품학회 2013 한국축산식품학회지 Vol.33 No.3

Sodium chloride is used to improve various properties of processed meat products, e.g., taste, preservation, water binding capacity, texture, meat batter viscosity, safety, and flavor; however, many studies have shown that sodium chloride increases the resistance of many foodborne pathogens to heat and acid. Listeria monocytogenes has been isolated from various readyto- eat (RTE) meat and dairy products formulated with sodium chloride; therefore, the objective of this paper was to review the effects of sodium chloride on the physiological characteristics of L. monocytogenes. The exposure of L. monocytogenes to sodium chloride may increase biofilm formation on foods or food contact surfaces, virulence gene transcription, invasion of Caco-2 cells, and bacteriocin production, depending on L. monocytogenes strain and serotype as well as sodium chloride concentration. When L. monocytogenes cells were exposed to sodium chloride, their resistance to UV-C irradiation and freezing temperatures increased, but sodium chloride had no effect on their resistance to gamma irradiation. The morphological properties of L. monocytogenes, especially cell elongation and filament formation, also change in response to sodium chloride. These findings indicate that sodium chloride affects various physiological responses of L. monocytogenes and thus, the effect of sodium chloride on L. monocytogenes in RTE meat and dairy products needs to be considered with respect to food safety. Moreover, further studies of microbial risk assessment should be conducted to suggest an appropriate sodium chloride concentration in animal origin foods.

Probabilistic Models to Predict Listeria monocytogenes Growth at Low Concentrations of NaNO₂ and NaCl in Frankfurters

Gwak, Eunji,Oh, Mi-Hwa,Park, Beom-Young,Lee, Heeyoung,Lee, Soomin,Ha, Jimyeong,Lee, Jeeyeon,Kim, Sejeong,Choi, Kyoung-Hee,Yoon, Yohan Korean Society for Food Science of Animal Resource 2015 한국축산식품학회지 Vol.35 No.6

This study developed probabilistic models to describe Listeria monocytogenes growth responses in meat products with low concentrations of NaNO₂ and NaCl. A five-strain mixture of L. monocytogenes was inoculated in NBYE (nutrient broth plus 0.6% yeast extract) supplemented with NaNO₂ (0-141 ppm) and NaCl (0-1.75%). The inoculated samples were then stored under aerobic and anaerobic conditions at 4, 7, 10, 12, and 15℃ for up to 60 d. Growth response data [growth (1) or no growth (0)] for each combination were determined by turbidity. The growth response data were analyzed using logistic regression to predict the growth probability of L. monocytogenes as a function of NaNO₂ and NaCl. The model performance was validated with the observed growth responses. The effect of an obvious NaNO₂ and NaCl combination was not observed under aerobic storage condition, but the antimicrobial effect of NaNO₂ on the inhibition of L. monocytogenes growth generally increased as NaCl concentration increased under anaerobic condition, especially at 7-10℃. A single application of NaNO₂ or NaCl significantly (p<0.05) inhibited L. monocytogenes growth at 4-15℃, but the combination of NaNO₂ or NaCl more effectively (p<0.05) inhibited L. monocytogenes growth than single application of either compound under anaerobic condition. Validation results showed 92% agreement between predicted and observed growth response data. These results indicate that the developed model is useful in predicting L. monocytogenes growth response at low concentrations of NaNO₂ and NaCl, and the antilisterial effect of NaNO₂ increased by NaCl under anaerobic condition.

Probabilistic Models to Predict Listeria monocytogenes Growth at Low Concentrations of NaNO2 and NaCl in Frankfurters

곽은지,오미화,박범영,이희영,이수민,하지명,이지연,김세정,최경희,윤요한 한국축산식품학회 2015 한국축산식품학회지 Vol.35 No.6

This study developed probabilistic models to describe Listeria monocytogenes growth responses in meat products with low concentrations of NaNO2 and NaCl. A five-strain mixture of L. monocytogenes was inoculated in NBYE (nutrient broth plus 0.6% yeast extract) supplemented with NaNO2 (0-141 ppm) and NaCl (0-1.75%). The inoculated samples were then stored under aerobic and anaerobic conditions at 4, 7, 10, 12, and 15°C for up to 60 d. Growth response data [growth (1) or no growth (0)] for each combination were determined by turbidity. The growth response data were analyzed using logistic regression to predict the growth probability of L. monocytogenes as a function of NaNO2 and NaCl. The model performance was validated with the observed growth responses. The effect of an obvious NaNO2 and NaCl combination was not observed under aerobic storage condition, but the antimicrobial effect of NaNO2 on the inhibition of L. monocytogenes growth generally increased as NaCl concentration increased under anaerobic condition, especially at 7-10°C. A single application of NaNO2 or NaCl significantly (p<0.05) inhibited L. monocytogenes growth at 4-15°C, but the combination of NaNO2 or NaCl more effectively (p<0.05) inhibited L. monocytogenes growth than single application of either compound under anaerobic condition. Validation results showed 92% agreement between predicted and observed growth response data. These results indicate that the developed model is useful in predicting L. monocytogenes growth response at low concentrations of NaNO2 and NaCl, and the antilisterial effect of NaNO2 increased by NaCl under anaerobic condition.

Probabilistic Models to Predict Listeria monocytogenes Growth at Low Concentrations of NaNO2 and NaCl in Frankfurters

Eunji Gwak,Mi Hwa Oh,Beom Young Park,Heeyoung Lee,Soomin Lee,Jimyeong Ha,Jeeyeon Lee,Sejeong Kim,Kyoung Hee Choi 한국축산식품학회 2015 한국축산식품학회지 Vol.35 No.6

This study developed probabilistic models to describe Listeria monocytogenes growth responses in meat products with low concentrations of NaNO2 and NaCl. A five-strain mixture of L. monocytogenes was inoculated in NBYE (nutrient broth plus 0.6% yeast extract) supplemented with NaNO2 (0-141 ppm) and NaCl (0-1.75%). The inoculated samples were then stored under aerobic and anaerobic conditions at 4, 7, 10, 12, and 15°C for up to 60 d. Growth response data [growth (1) or no growth (0)] for each combination were determined by turbidity. The growth response data were analyzed using logistic regression to predict the growth probability of L. monocytogenes as a function of NaNO2 and NaCl. The model performance was validated with the observed growth responses. The effect of an obvious NaNO2 and NaCl combination was not observed under aerobic storage condition, but the antimicrobial effect of NaNO2 on the inhibition of L. monocytogenes growth generally increased as NaCl concentration increased under anaerobic condition, especially at 7-10°C. A single application of NaNO2 or NaCl significantly (p<0.05) inhibited L. monocytogenes growth at 4-15°C, but the combination of NaNO2 or NaCl more effectively (p<0.05) inhibited L. monocytogenes growth than single application of either compound under anaerobic condition. Validation results showed 92% agreement between predicted and observed growth response data. These results indicate that the developed model is useful in predicting L. monocytogenes growth response at low concentrations of NaNO2 and NaCl, and the antilisterial effect of NaNO2 increased by NaCl under anaerobic condition.