The growth and survival characteristic of Salmonella Enteritidis under acidic and osmotic conditions were studied.Meanwhile,a probabilistic model based on the theory of cell division and mortality was established to p...The growth and survival characteristic of Salmonella Enteritidis under acidic and osmotic conditions were studied.Meanwhile,a probabilistic model based on the theory of cell division and mortality was established to predict the growth or inactivation of S.Enteritidis.The experimental results demonstrated that the growth curves of planktonic and detached cells showed a significant difference(p<0.05)under four conditions,including pH5.0+0.0%NaCl,pH7.0+4.0%NaCl,pH6.0+4.0%NaCl,and pH5.0+4.0%NaCl.And the established primary and secondary models could describe the growth of S.enteritis well by estimating four mathematics evaluation indexes,including determination coefficient(R2),root mean square error(RMSE),accuracy factor(Af)and bias factor(Bf).Moreover,sequential treatment of 15%NaCl stress followed by pH 4.5 stress was the best condition to inactivate S.Enteritidis in 10 h at 25◦C.The probabilistic model with Logistical or Weibullian form could also predict the inactivation of S.Enteritidis well,thus realize the unification of predictive model to some extent or generalization of inactivation model.Furthermore,the primary 4-parameter probabilistic model or generalized inactivation model had slightly higher applicability and reliability to describe the growth or inactivation of S.Enteritidis than Baranyi model or exponential inactivation model within the experimental range in this study.展开更多
Salmonella enterica serovar 1,4,[5],12:i:-(S.1,4,[5],12:i:-)has been recognized as an emerging foodborne pathogen in recent years.It can cause human salmonellosis predominated by the contamination of animal-derived fo...Salmonella enterica serovar 1,4,[5],12:i:-(S.1,4,[5],12:i:-)has been recognized as an emerging foodborne pathogen in recent years.It can cause human salmonellosis predominated by the contamination of animal-derived foods such as raw poultry and pork.This study aimed to characterize the genetic diversity,plasmid replicon types,and antibiotic resistance of 15 S.1,4,[5],12:i:-environmental isolates collected from two poultry farms using pulsed-field gel electrophoresis(PFGE),multilocus sequence typing(MLST),polymerase chain reaction-based replicon typing,and minimum inhibitory concentration approach.Ten different PFGE genotypes were detected,indicating a high diversity among these S.1,4,[5],12:i:-isolates.Three sequence types(ST19,ST1544,ST34)were identified by MLST.Among them,ST1544 was first detected in S.1,4,[5],12:i:-environmental isolates from poultry farms.All isolates were resistant to cefazolin,cefotetan,tobramycin,amikacin,and gentamicin,but susceptible to piperacillin-tazobactam,aztreonam,ceftazidime,cefepime,and ertapenem.Five incompatibility groups(Inc)of plasmids were identified,including IncFIIs(66.7%),IncHI2(20%),IncI1(6.7%),IncN(6.7%),and IncQ(6.7%).Among these isolates,80%carried at least one plasmid replicon type,and 20%carried multiple plasmid replicon types.Interestingly,the multidrug-resistant isolate 263 carried numerous resistance genes(i.e.qnrS,aac(6ʹ)-Ib-cr,bla_(TEM),bla_(CTX-M-9),bla_(OXA-1),sul1,sul2,sul3,floR,and mcr-1)and class I integronase gene intI1,which possessed both IncHI2 and IncQ plasmids,suggesting that resistance genes may be horizontally transferred by the combination of IncHI2 and IncQ plasmids.Collectively,antibiotic-resistant S.1,4,[5],12:i:-isolates were first found in poultry farm environments in China,and surveillance should be strengthened to prevent their further spread from poultry farms to foods.展开更多
Listeria monocytogenes(L.monocytogenes),a foodborne pathogen,can cause human listeriosis.Listeriosis is a potentially fatal gastrointestinal illness,which is closely related to the spread of food to humans.We review t...Listeria monocytogenes(L.monocytogenes),a foodborne pathogen,can cause human listeriosis.Listeriosis is a potentially fatal gastrointestinal illness,which is closely related to the spread of food to humans.We review the literature published during 2010-2019 to better understand the prevalence of L.monocytogenes in food products,incidence of human listeriosis,and their characteristics in Chinese mainland.We found the main sequence types(STs)strains from foods are similar globally,and the prevalence of L.monocytogenes from raw meat was the highest among all food products.The most common STs in food products and clinical cases were ST9(serogroup I.2)strains and ST87(serogroup Il.2)strains,respectively.The ST87 strains being the most common STs of clinical cases might be related to the existence of Listeria pathogenicity island 4 gene and Chinese eating habits for ready-to-eat foods,among which the prevalence of ST87 strain was the highest in ready-to-eat foods.Therefore,more research should be conducted to explore the reasons for the L.monocytogenes isolates differences in food and clinical sources.展开更多
Small berries including strawberry and blueberry are extensively consumed fruits with great economic values due to their characteristic flavor and appearance as well as potential health benefits.This review elaborated...Small berries including strawberry and blueberry are extensively consumed fruits with great economic values due to their characteristic flavor and appearance as well as potential health benefits.This review elaborated the optical non-destructive techniques viz.Vis-NIR spectroscopy,computer vision system,hyperspectral imaging,multispectral imaging,laser-induced method and thermal imaging,and their applications for quality and safety control of small berry fruits.The discussion regarding the photoacoustic technique,X-ray technique,Terahertz spectroscopy,odor imaging,micro-destructive testing and smart mobile terminal-based analyzer was also presented.Furthermore,we proposed our personal understanding of the technical challenges and further trends for these optical non-destructive techniques:1)owing to the relatively low detection limit,the so-called micro-destructive techniques may be alternative to the traditional non-destructive techniques in both practical and fundamental research;2)we suggest that the research articles like“collecting data first,and then modeling the relevant properties of agricultural products by machine learning”should be less produced in related fields.That's because such research methods are likely to be suspected of“cheating”.It is recommended that some modeling competitions can be carried out in the agricultural engineering field to avoid or reduce the“cheating”model.展开更多
基金This work has been financially supported by the National Natural Science Foundation of China(NSFC 31271896 and 31371776)the project in the National Science&Technology Pillar Program during the Twelfth Five-year Plan Period(2015BAK36B04)and the project of Science and Technology Commission of Shanghai Municipality(15395810900).
文摘The growth and survival characteristic of Salmonella Enteritidis under acidic and osmotic conditions were studied.Meanwhile,a probabilistic model based on the theory of cell division and mortality was established to predict the growth or inactivation of S.Enteritidis.The experimental results demonstrated that the growth curves of planktonic and detached cells showed a significant difference(p<0.05)under four conditions,including pH5.0+0.0%NaCl,pH7.0+4.0%NaCl,pH6.0+4.0%NaCl,and pH5.0+4.0%NaCl.And the established primary and secondary models could describe the growth of S.enteritis well by estimating four mathematics evaluation indexes,including determination coefficient(R2),root mean square error(RMSE),accuracy factor(Af)and bias factor(Bf).Moreover,sequential treatment of 15%NaCl stress followed by pH 4.5 stress was the best condition to inactivate S.Enteritidis in 10 h at 25◦C.The probabilistic model with Logistical or Weibullian form could also predict the inactivation of S.Enteritidis well,thus realize the unification of predictive model to some extent or generalization of inactivation model.Furthermore,the primary 4-parameter probabilistic model or generalized inactivation model had slightly higher applicability and reliability to describe the growth or inactivation of S.Enteritidis than Baranyi model or exponential inactivation model within the experimental range in this study.
基金supported by the National Natural Science Foundation of China(No.32102111)the Project was funded by the China Postdoctoral Science Foundation(2021M702194).
文摘Salmonella enterica serovar 1,4,[5],12:i:-(S.1,4,[5],12:i:-)has been recognized as an emerging foodborne pathogen in recent years.It can cause human salmonellosis predominated by the contamination of animal-derived foods such as raw poultry and pork.This study aimed to characterize the genetic diversity,plasmid replicon types,and antibiotic resistance of 15 S.1,4,[5],12:i:-environmental isolates collected from two poultry farms using pulsed-field gel electrophoresis(PFGE),multilocus sequence typing(MLST),polymerase chain reaction-based replicon typing,and minimum inhibitory concentration approach.Ten different PFGE genotypes were detected,indicating a high diversity among these S.1,4,[5],12:i:-isolates.Three sequence types(ST19,ST1544,ST34)were identified by MLST.Among them,ST1544 was first detected in S.1,4,[5],12:i:-environmental isolates from poultry farms.All isolates were resistant to cefazolin,cefotetan,tobramycin,amikacin,and gentamicin,but susceptible to piperacillin-tazobactam,aztreonam,ceftazidime,cefepime,and ertapenem.Five incompatibility groups(Inc)of plasmids were identified,including IncFIIs(66.7%),IncHI2(20%),IncI1(6.7%),IncN(6.7%),and IncQ(6.7%).Among these isolates,80%carried at least one plasmid replicon type,and 20%carried multiple plasmid replicon types.Interestingly,the multidrug-resistant isolate 263 carried numerous resistance genes(i.e.qnrS,aac(6ʹ)-Ib-cr,bla_(TEM),bla_(CTX-M-9),bla_(OXA-1),sul1,sul2,sul3,floR,and mcr-1)and class I integronase gene intI1,which possessed both IncHI2 and IncQ plasmids,suggesting that resistance genes may be horizontally transferred by the combination of IncHI2 and IncQ plasmids.Collectively,antibiotic-resistant S.1,4,[5],12:i:-isolates were first found in poultry farm environments in China,and surveillance should be strengthened to prevent their further spread from poultry farms to foods.
基金supported by the National Key Research and Development Program of China (No.2019YFE0103800).
文摘Listeria monocytogenes(L.monocytogenes),a foodborne pathogen,can cause human listeriosis.Listeriosis is a potentially fatal gastrointestinal illness,which is closely related to the spread of food to humans.We review the literature published during 2010-2019 to better understand the prevalence of L.monocytogenes in food products,incidence of human listeriosis,and their characteristics in Chinese mainland.We found the main sequence types(STs)strains from foods are similar globally,and the prevalence of L.monocytogenes from raw meat was the highest among all food products.The most common STs in food products and clinical cases were ST9(serogroup I.2)strains and ST87(serogroup Il.2)strains,respectively.The ST87 strains being the most common STs of clinical cases might be related to the existence of Listeria pathogenicity island 4 gene and Chinese eating habits for ready-to-eat foods,among which the prevalence of ST87 strain was the highest in ready-to-eat foods.Therefore,more research should be conducted to explore the reasons for the L.monocytogenes isolates differences in food and clinical sources.
基金This work was supported by the Shanghai Sailing Program under Grant 19YF1414100the China Postdoctoral Science Foundation funded project under Grant 2016M600315+1 种基金the Innovation Fund Project for Graduate Student of Shanghai(JWCXSL1401)the STCSM(No.18DZ2270700).
文摘Small berries including strawberry and blueberry are extensively consumed fruits with great economic values due to their characteristic flavor and appearance as well as potential health benefits.This review elaborated the optical non-destructive techniques viz.Vis-NIR spectroscopy,computer vision system,hyperspectral imaging,multispectral imaging,laser-induced method and thermal imaging,and their applications for quality and safety control of small berry fruits.The discussion regarding the photoacoustic technique,X-ray technique,Terahertz spectroscopy,odor imaging,micro-destructive testing and smart mobile terminal-based analyzer was also presented.Furthermore,we proposed our personal understanding of the technical challenges and further trends for these optical non-destructive techniques:1)owing to the relatively low detection limit,the so-called micro-destructive techniques may be alternative to the traditional non-destructive techniques in both practical and fundamental research;2)we suggest that the research articles like“collecting data first,and then modeling the relevant properties of agricultural products by machine learning”should be less produced in related fields.That's because such research methods are likely to be suspected of“cheating”.It is recommended that some modeling competitions can be carried out in the agricultural engineering field to avoid or reduce the“cheating”model.