International journal of food microbiology最新文献_第5页

The impact of fermentation length and dough composition on the stability of liquid sourdough starters 发酵时间和面团成分对液体酸面团起动剂稳定性的影响

IF 5 1区农林科学 Q1 FOOD SCIENCE & TECHNOLOGY

International journal of food microbiology

Pub Date : 2024-10-08 DOI: 10.1016/j.ijfoodmicro.2024.110932

Charlotte Bauer Munch-Andersen, Davide Porcellato, Tove Gulbrandsen Devold, Hilde Marit Østlie

Sourdough breadmaking on an industrial scale requires robust, well-performing starters that bring attractive characteristics to the product. The active nature of liquid starters provides a faster fermentation process compared to their dehydrated counterparts. However, liquid sourdough starters require meticulous management in order to maintain stability and functionality during cold storage at 4 °C.

This study investigated the stability of three liquid sourdough starters during storage and also the impact of prolonged fermentation, the addition of diastatic malted wheat flour, and a neutralising agent (CaCO₃).

The sourdough starters were evaluated for their microbial viability and metabolic activity at three individual time points during 16 weeks of cold storage. The microbial composition was analysed using culture-dependent and culture-independent methods, and metabolic changes were investigated using chromatographic methods.

Two types of sourdough starter showed satisfying viability of lactic acid bacteria (> 7 log CFU/g) and metabolic stability throughout 16 weeks of cold storage. The introduction of malted wheat flour and CaCO₃ caused a decline in viability to <7 log CFU/g within 8 weeks in the third sourdough starter type and additionally revealed an ongoing metabolic activity of this sourdough starter during cold storage.

Prolonged fermentation influenced the free amino acid profile, whereas adjusting the sourdough starter formula resulted in a different fungal microbiota and increased levels of fermentable substrates (maltose), organic acids (lactic acid), and aromatic compounds (alcohol and aldehydes).

These findings provide stakeholders and researchers in sourdough fermentation technology with new insights concerning the stability of cold-stored liquid sourdough starters.

工业化规模的酸包制作需要坚固耐用、性能良好的发酵剂，这样才能为产品带来诱人的特性。与脱水的发酵剂相比，液态发酵剂的活性可加快发酵过程。本研究调查了三种液体酸包粉起发酵剂在贮藏过程中的稳定性，以及延长发酵时间、添加泻盐麦芽粉和中和剂（CaCO3）的影响。在 16 周的冷藏期间，对酸包粉起发酵剂在三个时间点的微生物活力和代谢活性进行了评估。在 16 周的冷藏过程中，两种酸面团发酵剂都表现出了令人满意的乳酸菌活力（7 log CFU/g）和新陈代谢稳定性。引入麦芽粉和 CaCO3 后，第三种酸包粉起发酵剂的存活率在 8 周内下降到 7 log CFU/g，此外还显示这种酸包粉起发酵剂在冷藏期间具有持续的新陈代谢活动。延长发酵时间会影响游离氨基酸谱，而调整酸面团起动菌配方则会导致不同的真菌微生物群以及可发酵基质（麦芽糖）、有机酸（乳酸）和芳香化合物（酒精和醛）水平的增加。

{"title":"The impact of fermentation length and dough composition on the stability of liquid sourdough starters","authors":"Charlotte Bauer Munch-Andersen, Davide Porcellato, Tove Gulbrandsen Devold, Hilde Marit Østlie","doi":"10.1016/j.ijfoodmicro.2024.110932","DOIUrl":"10.1016/j.ijfoodmicro.2024.110932","url":null,"abstract":"<div><div>Sourdough breadmaking on an industrial scale requires robust, well-performing starters that bring attractive characteristics to the product. The active nature of liquid starters provides a faster fermentation process compared to their dehydrated counterparts. However, liquid sourdough starters require meticulous management in order to maintain stability and functionality during cold storage at 4 °C.</div><div>This study investigated the stability of three liquid sourdough starters during storage and also the impact of prolonged fermentation, the addition of diastatic malted wheat flour, and a neutralising agent (CaCO<sub>3</sub>).</div><div>The sourdough starters were evaluated for their microbial viability and metabolic activity at three individual time points during 16 weeks of cold storage. The microbial composition was analysed using culture-dependent and culture-independent methods, and metabolic changes were investigated using chromatographic methods.</div><div>Two types of sourdough starter showed satisfying viability of lactic acid bacteria (> 7 log CFU/g) and metabolic stability throughout 16 weeks of cold storage. The introduction of malted wheat flour and CaCO<sub>3</sub> caused a decline in viability to <7 log CFU/g within 8 weeks in the third sourdough starter type and additionally revealed an ongoing metabolic activity of this sourdough starter during cold storage.</div><div>Prolonged fermentation influenced the free amino acid profile, whereas adjusting the sourdough starter formula resulted in a different fungal microbiota and increased levels of fermentable substrates (maltose), organic acids (lactic acid), and aromatic compounds (alcohol and aldehydes).</div><div>These findings provide stakeholders and researchers in sourdough fermentation technology with new insights concerning the stability of cold-stored liquid sourdough starters.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"426 ","pages":"Article 110932"},"PeriodicalIF":5.0,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The role and the determination of the LuxI protein binding targets in the formation of biogenic amines in Hafnia alvei H4 在 Hafnia alvei H4 中形成生物胺过程中 LuxI 蛋白结合目标的作用和确定。

IF 5 1区农林科学 Q1 FOOD SCIENCE & TECHNOLOGY

International journal of food microbiology

Pub Date : 2024-10-05 DOI: 10.1016/j.ijfoodmicro.2024.110928

Xue Li , Yanan Wang , Gongliang Zhang , Jingran Bi , Hongshun Hao , Hongman Hou

Hafnia alvei is a spoilage microorganism that possesses the LuxI/LuxR-type quorum sensing (QS) system. Biogenic amines (BAs) are important in food spoilage and safety, yet the role of QS in BA formation remains poorly understood. This study investigated the ability of H. alvei H4 to produce BAs in fish flesh and decarboxylase culture media. The findings showed that H. alvei H4 produced substantial amounts of putrescine and cadaverine in turbot flesh, with its enhanced amine-producing capacity potentially leading to the eventual deterioration of the fish. Furthermore, the deletion of the QS element—AHL synthase gene luxI—affected the concentrations of both BAs. Based on these observations, the present study conducted multifaceted experiments, including phenotypic assessments and analyses of gene expression, to explore the role of luxI and to identify its specific binding targets. The results indicated that putrescine formation in H. alvei H4 primarily occurred via the arginine deiminase (ADI) pathway, with luxI playing a positive role in the conversion of arginine to ornithine and subsequently to putrescine. The reduction in putrescine content observed in a luxI mutant (ΔluxI) was attributed to the direct binding of the LuxI protein to the promoters of the argF and speC genes, which code for ornithine carbamoyltransferase and ornithine decarboxylase, respectively. The findings of this study provided the basis to understand the influence of QS on BA production in H. alvei, by specifically demonstrating the involvement of the luxI gene on putrescine and cadaverine production.

Hafnia alvei 是一种具有 LuxI/LuxR 型法定量感应（QS）系统的腐败微生物。生物胺（BA）在食品腐败和安全方面具有重要作用，但人们对 QS 在生物胺形成过程中的作用仍然知之甚少。本研究调查了白喉杆菌 H4 在鱼肉和脱羧酶培养基中产生 BAs 的能力。研究结果表明，H. alvei H4 能在多宝鱼肉中产生大量腐胺和尸胺，其产胺能力的增强可能会导致多宝鱼最终变质。此外，QS元件-AHL合成酶基因luxI的缺失也会影响这两种BA的浓度。基于这些观察结果，本研究进行了多方面的实验，包括表型评估和基因表达分析，以探索luxI的作用并确定其特定的结合靶标。结果表明，H. alvei H4中的腐胺主要是通过精氨酸脱氨酶（ADI）途径形成的，而luxI在精氨酸转化为鸟氨酸进而转化为腐胺的过程中发挥了积极作用。在luxI突变体（ΔluxI）中观察到的腐胺含量减少是由于LuxI蛋白与argF和speC基因的启动子直接结合所致，这两个基因分别编码鸟氨酸氨基甲酰转移酶和鸟氨酸脱羧酶。本研究的发现为了解 QS 对 H. alvei 产生 BA 的影响提供了基础，特别是证明了 luxI 基因参与了腐胺和尸胺的产生。

{"title":"The role and the determination of the LuxI protein binding targets in the formation of biogenic amines in Hafnia alvei H4","authors":"Xue Li , Yanan Wang , Gongliang Zhang , Jingran Bi , Hongshun Hao , Hongman Hou","doi":"10.1016/j.ijfoodmicro.2024.110928","DOIUrl":"10.1016/j.ijfoodmicro.2024.110928","url":null,"abstract":"<div><div><em>Hafnia alvei</em> is a spoilage microorganism that possesses the LuxI/LuxR-type quorum sensing (QS) system. Biogenic amines (BAs) are important in food spoilage and safety, yet the role of QS in BA formation remains poorly understood. This study investigated the ability of <em>H. alvei</em> H4 to produce BAs in fish flesh and decarboxylase culture media. The findings showed that <em>H. alvei</em> H4 produced substantial amounts of putrescine and cadaverine in turbot flesh, with its enhanced amine-producing capacity potentially leading to the eventual deterioration of the fish. Furthermore, the deletion of the QS element—AHL synthase gene <em>luxI</em>—affected the concentrations of both BAs. Based on these observations, the present study conducted multifaceted experiments, including phenotypic assessments and analyses of gene expression, to explore the role of <em>luxI</em> and to identify its specific binding targets. The results indicated that putrescine formation in <em>H. alvei</em> H4 primarily occurred via the arginine deiminase (ADI) pathway, with <em>luxI</em> playing a positive role in the conversion of arginine to ornithine and subsequently to putrescine. The reduction in putrescine content observed in a <em>luxI</em> mutant (Δ<em>luxI</em>) was attributed to the direct binding of the LuxI protein to the promoters of the <em>argF</em> and <em>speC</em> genes, which code for ornithine carbamoyltransferase and ornithine decarboxylase, respectively. The findings of this study provided the basis to understand the influence of QS on BA production in <em>H. alvei</em>, by specifically demonstrating the involvement of the <em>luxI</em> gene on putrescine and cadaverine production<em>.</em></div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"426 ","pages":"Article 110928"},"PeriodicalIF":5.0,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142406366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Disruption of the signal recognition particle pathway leading to impaired growth, sugar metabolism and acid resistance of Lactococcus lactis 信号识别颗粒途径中断导致乳酸乳球菌生长、糖代谢和耐酸性受损。

IF 5 1区农林科学 Q1 FOOD SCIENCE & TECHNOLOGY

International journal of food microbiology

Pub Date : 2024-10-04 DOI: 10.1016/j.ijfoodmicro.2024.110929

Meng Wang, Yanying Yue, Xiaoce Zhu, Mengjie Wang, Yifei Zhang, Jian Kong, Tingting Guo

Lactococcus lactis is a well-known workhorse for dairy products, whose important industrial traits are tightly associated with numerous cytoplasmic membrane proteins. However, roles of the signal recognition particle (SRP) pathway responsible for membrane protein targeting have not been studied in L. lactis. In this work, the putative genes ffh and ftsY encoding SRP pathway components were identified in the genome of L. lactis NZ9000. Experimental evidence showed that sequence mutation in either the ffh or ftsY was not lethal, but prolonged the lag phase of the resultant mutants Δffh and ΔftsY by 2 h and lowered their biomass to 85.7 % of the wild type under static conditions, as well as deprived the mutants of improved growth capacity under aerobic respiration conditions. Besides, the speeds of glucose consumption and lactate production were significantly decreased in the mutants. Then, the impact of the SPR components on acid resistance was detected, showing that the ffh and ftsY were transcriptionally upregulated by 3.02 ± 1.21 and 8.66 ± 1.01-fold in the wild type during acid challenge at pH 3.0, and cell survival of the Δffh and ΔftsY decreased by10- and 100-fold compared with the wild type. To explore the possible mechanism about the SRP pathway involved in the above physiological traits, proteomics analysis was performed and revealed that disruption of the Ffh or FtsY led to decrease in ribosomal proteins, but increase in DnaK, GroEL and heat shock protein GrpE, indicating that the SRP pathway was closely linked to protein synthesis and folding in L. lactis. Decrease in the fructose-bisphosphate aldolase, respiratory complexes NADH dehydrogenase, as well as glutamate decarboxylase was also detected in the Δffh and ΔftsY, which is consistent with the phenomena of impaired sugar metabolism and acid resistance. Our results demonstrated the dispensable SRP pathway could contribute to the maintenance of metabolism homeostasis and acid resistance of L. lactis.

乳酸乳球菌是众所周知的乳制品生产主力军，其重要的工业特性与众多细胞质膜蛋白密切相关。然而，在乳球菌中，负责膜蛋白靶向的信号识别颗粒（SRP）通路的作用尚未得到研究。在这项工作中，在乳酸菌 NZ9000 的基因组中发现了编码 SRP 通路元件的推定基因 ffh 和 ftsY。实验证明，ffh 或 ftsY 的序列突变并不致死，但会使突变体 Δffh 和 ΔftsY 的滞后期延长 2 小时，使其在静态条件下的生物量降至野生型的 85.7%，并使突变体在有氧呼吸条件下的生长能力下降。此外，突变体的葡萄糖消耗速度和乳酸生成速度也明显下降。结果表明，在pH 3.0的酸挑战条件下，野生型的ffh和ftsY转录上调了3.02±1.21倍和8.66±1.01倍，Δffh和ΔftsY的细胞存活率比野生型分别降低了10倍和100倍。为了探索SRP通路参与上述生理特性的可能机制，研究人员进行了蛋白质组学分析，结果表明干扰Ffh或FtsY会导致核糖体蛋白减少，但DnaK、GroEL和热休克蛋白GrpE会增加，这表明SRP通路与乳酸菌蛋白质的合成和折叠密切相关。在Δffh和ΔftsY中还检测到果糖-二磷酸醛缩酶、呼吸复合体NADH脱氢酶以及谷氨酸脱羧酶的减少，这与糖代谢受损和耐酸现象一致。我们的研究结果表明，可有可无的SRP途径有助于维持乳酸菌的代谢平衡和耐酸性。

{"title":"Disruption of the signal recognition particle pathway leading to impaired growth, sugar metabolism and acid resistance of Lactococcus lactis","authors":"Meng Wang, Yanying Yue, Xiaoce Zhu, Mengjie Wang, Yifei Zhang, Jian Kong, Tingting Guo","doi":"10.1016/j.ijfoodmicro.2024.110929","DOIUrl":"10.1016/j.ijfoodmicro.2024.110929","url":null,"abstract":"<div><div><em>Lactococcus lactis</em> is a well-known workhorse for dairy products, whose important industrial traits are tightly associated with numerous cytoplasmic membrane proteins. However, roles of the signal recognition particle (SRP) pathway responsible for membrane protein targeting have not been studied in <em>L. lactis</em>. In this work, the putative genes <em>ffh</em> and <em>ftsY</em> encoding SRP pathway components were identified in the genome of <em>L. lactis</em> NZ9000. Experimental evidence showed that sequence mutation in either the <em>ffh</em> or <em>ftsY</em> was not lethal, but prolonged the lag phase of the resultant mutants Δffh and ΔftsY by 2 h and lowered their biomass to 85.7 % of the wild type under static conditions, as well as deprived the mutants of improved growth capacity under aerobic respiration conditions. Besides, the speeds of glucose consumption and lactate production were significantly decreased in the mutants. Then, the impact of the SPR components on acid resistance was detected, showing that the <em>ffh</em> and <em>ftsY</em> were transcriptionally upregulated by 3.02 ± 1.21 and 8.66 ± 1.01-fold in the wild type during acid challenge at pH 3.0, and cell survival of the Δffh and ΔftsY decreased by10- and 100-fold compared with the wild type. To explore the possible mechanism about the SRP pathway involved in the above physiological traits, proteomics analysis was performed and revealed that disruption of the Ffh or FtsY led to decrease in ribosomal proteins, but increase in DnaK, GroEL and heat shock protein GrpE, indicating that the SRP pathway was closely linked to protein synthesis and folding in <em>L. lactis</em>. Decrease in the fructose-bisphosphate aldolase, respiratory complexes NADH dehydrogenase, as well as glutamate decarboxylase was also detected in the Δffh and ΔftsY, which is consistent with the phenomena of impaired sugar metabolism and acid resistance. Our results demonstrated the dispensable SRP pathway could contribute to the maintenance of metabolism homeostasis and acid resistance of <em>L. lactis</em>.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"426 ","pages":"Article 110929"},"PeriodicalIF":5.0,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The applicability of the SERS technique in food contamination testing – The detailed spectroscopic, chemometric, genetic, and comparative analysis of food-borne Cronobacter spp. strains SERS 技术在食品污染检测中的适用性 - 对食源性克罗诺杆菌属菌株进行详细的光谱、化学计量、遗传和比较分析。

IF 5 1区农林科学 Q1 FOOD SCIENCE & TECHNOLOGY

International journal of food microbiology

Pub Date : 2024-10-03 DOI: 10.1016/j.ijfoodmicro.2024.110930

K. Niciński , E. Witkowska , D. Korsak , M. Szuplewska , A. Kamińska

Microorganisms assigned as Cronobacter are Gram-negative, facultatively anaerobic, bacteria widely distributed in nature, home environments, and hospitals. They can also be detected in foods, milk powder, and powdered infant formula (PIF). Additionally, as an opportunistic pathogen, Cronobacter may cause serious infections, sometimes leading to the death of neonates and infants. Thus, it is essential to test food products for the presence of Cronobacter spp. The currently used standard described in ISO 22964:2017 is a laborious method that could be easily replaced by surface-enhanced Raman scattering (SERS).

Here, we demonstrate that SERS allows the identification of food-borne bacteria belonging to Cronobacter spp. based on their SERS spectra. For this purpose, twenty-six Cronobacter strains from different food samples were analyzed. Additionally, it was shown that it is possible to differentiate them from other closely related pathogens such as Salmonella enterica subsp. enterica, Escherichia coli, or Enterobacter spp. The SERS results were supported by principal component analysis (PCA), as well as and sequencing of 16S rRNA, rpoB and fusA genes. Last but not least, it was demonstrated that the cells of Cronobacter sakazakii may be easily separated from PIF using an appropriate filter, microfluidic chip, and dielectrophoresis (DEP) technique.

克罗诺杆菌是一种革兰氏阴性、兼性厌氧细菌，广泛分布于自然界、家庭环境和医院中。在食品、奶粉和婴儿配方粉（PIF）中也能检测到它们。此外，作为一种机会性病原体，克罗诺杆菌可能会引起严重感染，有时会导致新生儿和婴儿死亡。ISO 22964:2017 中描述的当前使用的标准是一种费力的方法，很容易被表面增强拉曼散射（SERS）所取代。在这里，我们证明了 SERS 可以根据其 SERS 光谱来识别属于克罗诺杆菌属的食源性细菌。为此，我们分析了来自不同食品样本的 26 株克罗诺杆菌。主成分分析（PCA）以及 16S rRNA、rpoB 和 fusA 基因的测序也支持了 SERS 的结果。最后但并非最不重要的一点是，该研究证明，使用适当的过滤器、微流控芯片和介电泳（DEP）技术，可以很容易地从 PIF 中分离出阪崎肠杆菌的细胞。

{"title":"The applicability of the SERS technique in food contamination testing – The detailed spectroscopic, chemometric, genetic, and comparative analysis of food-borne Cronobacter spp. strains","authors":"K. Niciński , E. Witkowska , D. Korsak , M. Szuplewska , A. Kamińska","doi":"10.1016/j.ijfoodmicro.2024.110930","DOIUrl":"10.1016/j.ijfoodmicro.2024.110930","url":null,"abstract":"<div><div>Microorganisms assigned as <em>Cronobacter</em> are Gram-negative, facultatively anaerobic, bacteria widely distributed in nature, home environments, and hospitals. They can also be detected in foods, milk powder, and powdered infant formula (PIF). Additionally, as an opportunistic pathogen, <em>Cronobacter</em> may cause serious infections, sometimes leading to the death of neonates and infants. Thus, it is essential to test food products for the presence of <em>Cronobacter</em> spp. The currently used standard described in ISO 22964:2017 is a laborious method that could be easily replaced by surface-enhanced Raman scattering (SERS).</div><div>Here, we demonstrate that SERS allows the identification of food-borne bacteria belonging to <em>Cronobacter</em> spp. based on their SERS spectra. For this purpose, twenty-six <em>Cronobacter</em> strains from different food samples were analyzed. Additionally, it was shown that it is possible to differentiate them from other closely related pathogens such as <em>Salmonella enterica</em> subsp. <em>enterica</em>, <em>Escherichia coli</em>, or <em>Enterobacter</em> spp. The SERS results were supported by principal component analysis (PCA), as well as and sequencing of 16S rRNA<em>, rpoB</em> and <em>fusA</em> genes. Last but not least, it was demonstrated that the cells of <em>Cronobacter sakazakii</em> may be easily separated from PIF using an appropriate filter, microfluidic chip, and dielectrophoresis (DEP) technique.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"426 ","pages":"Article 110930"},"PeriodicalIF":5.0,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142406365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High-pressure processing and heat treatment of Murrah buffalo milk: Comparative study on microbial changes during refrigerated storage Murrah 水牛奶的高压加工和热处理：冷藏期间微生物变化的比较研究。

IF 5 1区农林科学 Q1 FOOD SCIENCE & TECHNOLOGY

International journal of food microbiology

Pub Date : 2024-10-02 DOI: 10.1016/j.ijfoodmicro.2024.110926

Darren Sim Xuan Yu , Chong Kah Hui , Mohammad Rashedi Ismail-Fitry , Pankaj Koirala , Nilesh Nirmal , Mahmud Ab Rashid Nor-Khaizura

This study aims to evaluate the effect of high-pressure processing (HPP) (500 and 600 MPa for 3 min and 5 min) on the microbial changes of Murrah buffalo milk in comparison to heat treatment (72 °C for 15 s of holding time) during refrigerated storage of 28 days. The results indicated that the total plate count (TPC) of raw milk at day 0 was 5.5 ± 0.6 log₁₀ CFU/mL. At day 0, heat treatment lowered TPC to 3.9 ± 0.6, while HPP treatment was in the range of 4.1 ± 0.3 to 4.8 ± 0.6 log₁₀ CFU/mL. Similarly, lowered yeast and mold count and lactic acid bacteria were noted in heat- and HPP-treated milk samples compared to the control sample during refrigerated storage. There were no Staphylococcus aureus and Escherichia coli detected in heat and HPP-treated samples. Heat or HPP treatment at 600 MPa for 5 min significantly extended the shelf-life of Murrah buffalo milk for three weeks at the refrigerated storage. In addition, HPP treatment did not alter the pH, lightness (L* value), protein, or fat content of Murrah buffalo milk during refrigerated storage. Hence HPP at 600 MPa for 5 min could be a suitable alternative to conventional heat treatment.

本研究旨在评估在冷藏贮存 28 天期间，高压处理（HPP，500 和 600 兆帕，3 分钟和 5 分钟）与热处理（72 °C，15 秒保温时间）相比对穆拉拉水牛奶微生物变化的影响。结果表明，生牛奶在第 0 天时的菌落总数（TPC）为 5.5 ± 0.6 log10 CFU/mL。在第 0 天，热处理将 TPC 降至 3.9 ± 0.6，而 HPP 处理的范围为 4.1 ± 0.3 至 4.8 ± 0.6 log10 CFU/mL。同样，与冷藏储存期间的对照样本相比，加热和 HPP 处理过的牛奶样本中的酵母菌、霉菌和乳酸菌数量也有所减少。在加热和 HPP 处理过的样品中没有检测到金黄色葡萄球菌和大肠杆菌。在 600 兆帕的压力下加热或 HPP 处理 5 分钟可明显延长伊拉水牛奶在冷藏条件下三周的货架期。此外，在冷藏储存期间，HPP 处理不会改变伊拉水牛奶的 pH 值、亮度（L* 值）、蛋白质或脂肪含量。因此，在 600 兆帕的压力下进行 5 分钟的 HPP 可作为传统热处理的合适替代方法。

{"title":"High-pressure processing and heat treatment of Murrah buffalo milk: Comparative study on microbial changes during refrigerated storage","authors":"Darren Sim Xuan Yu , Chong Kah Hui , Mohammad Rashedi Ismail-Fitry , Pankaj Koirala , Nilesh Nirmal , Mahmud Ab Rashid Nor-Khaizura","doi":"10.1016/j.ijfoodmicro.2024.110926","DOIUrl":"10.1016/j.ijfoodmicro.2024.110926","url":null,"abstract":"<div><div>This study aims to evaluate the effect of high-pressure processing (HPP) (500 and 600 MPa for 3 min and 5 min) on the microbial changes of Murrah buffalo milk in comparison to heat treatment (72 °C for 15 s of holding time) during refrigerated storage of 28 days. The results indicated that the total plate count (TPC) of raw milk at day 0 was 5.5 ± 0.6 log<sub>10</sub> CFU/mL. At day 0, heat treatment lowered TPC to 3.9 ± 0.6, while HPP treatment was in the range of 4.1 ± 0.3 to 4.8 ± 0.6 log<sub>10</sub> CFU/mL. Similarly, lowered yeast and mold count and lactic acid bacteria were noted in heat- and HPP-treated milk samples compared to the control sample during refrigerated storage. There were no <em>Staphylococcus aureus</em> and <em>Escherichia coli</em> detected in heat and HPP-treated samples. Heat or HPP treatment at 600 MPa for 5 min significantly extended the shelf-life of Murrah buffalo milk for three weeks at the refrigerated storage. In addition, HPP treatment did not alter the pH, lightness (<em>L</em>* value), protein, or fat content of Murrah buffalo milk during refrigerated storage. Hence HPP at 600 MPa for 5 min could be a suitable alternative to conventional heat treatment.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"426 ","pages":"Article 110926"},"PeriodicalIF":5.0,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142377917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Genomic and phenotypic polymorphism of Clostridium botulinum Group II strain Beluga through laboratory domestication 通过实验室驯化白鲸肉毒梭菌 II 型菌株的基因组和表型多态性。

IF 5 1区农林科学 Q1 FOOD SCIENCE & TECHNOLOGY

International journal of food microbiology

Pub Date : 2024-10-01 DOI: 10.1016/j.ijfoodmicro.2024.110927

Katja Selby, François P. Douillard, Miia Lindström

Laboratory domestication is the result of genetic and physiological changes of organisms acquired during numerous passages in vitro. This phenomenon has been observed in bacteria as well as in higher organisms. In an effort to understand the impact of laboratory domestication on the foodborne pathogen Clostridium botulinum and related microbial food safety research, we investigated multiple spore stocks of C. botulinum Group II Beluga from our collection, as that is a widely applied model strain used in laboratories over decades. An acquired nutrient auxotrophy was confirmed as thymidine dependency using phenotypic microarrays. In parallel, whole-genome re-sequencing of all stocks revealed a mutation in thyA encoding thymidylate synthase essential for de-novo synthesis of dTMP from dUMP in the auxotrophic stocks. A thyA-deficient Beluga variant stock was successfully complemented by introducing an intact variant of thyA and thymidine prototrophy was restored, indicating that the thymidine auxotrophy was solely due to the presence of a SNP in thyA. Our data suggested that this mutation, deleterious under nutrient-poor growth conditions in a chemically defined medium, has been present and maintained in laboratory stocks for nearly 30 years. Yet, the mutation remained unidentified since receiving the strain, most likely due to routine use of culture conditions optimized for growth performance. This work pinpoints the need for careful monitoring of model strains extensively used in laboratory settings at both phenotypic and genomic level. In applications like food safety challenge tests, compromised strains could cause incorrect predictions and thereby have deleterious consequences. To mitigate the risk of acquiring mutations, we recommend keeping passage numbers of laboratory strains low and to avoid single-colony passaging. In addition, relevant strains should be subjected to regular WGS checks and physiological validation to exclude DNA mutations with potential negative impacts on research data integrity and reproducibility.

实验室驯化是生物体在体外多次传代过程中遗传和生理变化的结果。在细菌和高等生物体中都观察到了这种现象。为了了解实验室驯化对食源性致病菌肉毒梭菌和相关微生物食品安全研究的影响，我们研究了我们收集的肉毒梭菌第二类白鲸孢子种群，因为这是几十年来实验室广泛使用的模式菌株。使用表型芯片确认了一种获得性营养物质辅助营养，即胸腺嘧啶依赖性。与此同时，对所有种群进行的全基因组重测序发现，在辅助营养型种群中，编码胸苷酸合成酶的 thyA 发生了突变，而这种突变对于从 dUMP 中重新合成 dTMP 至关重要。通过引入一个完整的 thyA 变体，成功地对一个 thyA 缺陷白鲸变体种群进行了互补，胸苷原生营养得以恢复，这表明胸苷辅助营养完全是由于 thyA 中存在一个 SNP。我们的数据表明，这种突变在化学定义的培养基中营养贫乏的生长条件下是有害的，它已经在实验室种群中存在并维持了近 30 年。然而，自接收菌株以来，该突变仍未被发现，这很可能是由于常规使用了优化生长性能的培养条件。这项工作表明，有必要在表型和基因组水平上对实验室中广泛使用的模式菌株进行仔细监测。在食品安全挑战测试等应用中，受损菌株可能会导致预测错误，从而产生有害后果。为了降低获得突变的风险，我们建议保持实验室菌株较低的传代次数，避免单菌落传代。此外，应定期对相关菌株进行 WGS 检查和生理验证，以排除对研究数据完整性和可重复性有潜在负面影响的 DNA 变异。

{"title":"Genomic and phenotypic polymorphism of Clostridium botulinum Group II strain Beluga through laboratory domestication","authors":"Katja Selby, François P. Douillard, Miia Lindström","doi":"10.1016/j.ijfoodmicro.2024.110927","DOIUrl":"10.1016/j.ijfoodmicro.2024.110927","url":null,"abstract":"<div><div>Laboratory domestication is the result of genetic and physiological changes of organisms acquired during numerous passages <em>in vitro</em>. This phenomenon has been observed in bacteria as well as in higher organisms. In an effort to understand the impact of laboratory domestication on the foodborne pathogen <em>Clostridium botulinum</em> and related microbial food safety research, we investigated multiple spore stocks of <em>C. botulinum</em> Group II Beluga from our collection, as that is a widely applied model strain used in laboratories over decades. An acquired nutrient auxotrophy was confirmed as thymidine dependency using phenotypic microarrays. In parallel, whole-genome re-sequencing of all stocks revealed a mutation in <em>thyA</em> encoding thymidylate synthase essential for <em>de-novo</em> synthesis of dTMP from dUMP in the auxotrophic stocks. A <em>thyA</em>-deficient Beluga variant stock was successfully complemented by introducing an intact variant of <em>thyA</em> and thymidine prototrophy was restored, indicating that the thymidine auxotrophy was solely due to the presence of a SNP in <em>thyA</em>. Our data suggested that this mutation, deleterious under nutrient-poor growth conditions in a chemically defined medium, has been present and maintained in laboratory stocks for nearly 30 years. Yet, the mutation remained unidentified since receiving the strain, most likely due to routine use of culture conditions optimized for growth performance. This work pinpoints the need for careful monitoring of model strains extensively used in laboratory settings at both phenotypic and genomic level. In applications like food safety challenge tests, compromised strains could cause incorrect predictions and thereby have deleterious consequences. To mitigate the risk of acquiring mutations, we recommend keeping passage numbers of laboratory strains low and to avoid single-colony passaging. In addition, relevant strains should be subjected to regular WGS checks and physiological validation to exclude DNA mutations with potential negative impacts on research data integrity and reproducibility.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"426 ","pages":"Article 110927"},"PeriodicalIF":5.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Antibiofilm mechanism of 2R,3R-dihydromyricetin by targeting sortase A and its application against Staphylococcus aureus adhesion on eggshell 2R,3R-二氢杨梅素通过靶向分选酶 A 的抗生物膜机制及其在蛋壳上金黄色葡萄球菌粘附中的应用。

IF 5 1区农林科学 Q1 FOOD SCIENCE & TECHNOLOGY

International journal of food microbiology

Pub Date : 2024-09-30 DOI: 10.1016/j.ijfoodmicro.2024.110925

Wenyi Ran , Peirui Yi , Ling Jiang, Yang Yu, Kai Zhong, Yanping Wu, Hong Gao

Biofilm formation of Staphylococcus aureus in food processing environments raises significant safety concerns, necessitating the development of new antibiofilm approaches for controlling S. aureus contamination. This study aimed to elucidate the antibiofilm mechanism of 2R,3R-dihydromyricetin (DMY), a natural flavonoid, against S. aureus and evaluate its efficacy in reducing bacterial adhesion to eggshell. The results revealed that DMY was a potent inhibitor of S. aureus sortase A (SrtA) with an IC₅₀ of 73.43 μM, preventing bacterial adhesion to fibrinogen and subsequent biofilm formation. Fluorescence quenching assay and surface plasmon resonance analysis confirmed that DMY could directly bind to S. aureus SrtA. Notably, circular dichroism spectra demonstrated a conformational change in SrtA from α-helical to β-sheet structure upon DMY binding. Molecular dynamics simulation suggested that DMY bound to the catalytic pocket of S. aureus SrtA via hydrophobic interactions and hydrogen bonds. Furthermore, fluorescence microscopic observations further revealed that DMY attenuated the biofilm-related phenotype of SrtA by decreasing the anchoring of S. aureus protein A (SpA) onto cell wall. Importantly, pretreatment with 125 μg/mL DMY significantly reduced 1.14–1.75 log CFU/cm² of S. aureus adhered on eggshells. Overall, these findings highlight how specific targeting of SrtA by DMY inhibits the attachment stages of biofilm development in S. aureus, making it a promising candidate for a novel disinfectant against this pathogen in the food industry.

金黄色葡萄球菌在食品加工环境中形成的生物膜引发了严重的安全问题，因此有必要开发新的抗生物膜方法来控制金黄色葡萄球菌污染。本研究旨在阐明天然黄酮类化合物 2R,3R-二氢杨梅素（DMY）对金黄色葡萄球菌的抗生物膜机制，并评估其减少细菌粘附蛋壳的功效。结果表明，DMY 是金黄色葡萄球菌分选酶 A（SrtA）的强效抑制剂，其 IC50 值为 73.43 μM，可阻止细菌粘附到纤维蛋白原上并随后形成生物膜。荧光淬灭试验和表面等离子体共振分析证实，DMY 可直接与金黄色葡萄球菌 SrtA 结合。值得注意的是，圆二色性光谱显示，DMY 与 SrtA 结合后，SrtA 的构象发生了变化，从 α 螺旋结构变为 β 片状结构。分子动力学模拟表明，DMY 是通过疏水作用和氢键与金黄色葡萄球菌 SrtA 的催化袋结合的。此外，荧光显微镜观察进一步发现，DMY通过降低金黄色葡萄球菌蛋白A（SpA）在细胞壁上的锚定作用，减弱了SrtA的生物膜相关表型。重要的是，用 125 μg/mL DMY 预处理可显著减少蛋壳上金黄色葡萄球菌的 1.14-1.75 log CFU/cm2。总之，这些研究结果突显了 DMY 对 SrtA 的特异性靶向作用如何抑制金黄色葡萄球菌生物膜发展的附着阶段，使其成为食品工业中针对这种病原体的新型消毒剂的理想候选物。

{"title":"Antibiofilm mechanism of 2R,3R-dihydromyricetin by targeting sortase A and its application against Staphylococcus aureus adhesion on eggshell","authors":"Wenyi Ran , Peirui Yi , Ling Jiang, Yang Yu, Kai Zhong, Yanping Wu, Hong Gao","doi":"10.1016/j.ijfoodmicro.2024.110925","DOIUrl":"10.1016/j.ijfoodmicro.2024.110925","url":null,"abstract":"<div><div>Biofilm formation of <em>Staphylococcus aureus</em> in food processing environments raises significant safety concerns, necessitating the development of new antibiofilm approaches for controlling <em>S. aureus</em> contamination. This study aimed to elucidate the antibiofilm mechanism of <em>2R</em>,<em>3R</em>-dihydromyricetin (DMY), a natural flavonoid, against <em>S. aureus</em> and evaluate its efficacy in reducing bacterial adhesion to eggshell. The results revealed that DMY was a potent inhibitor of <em>S. aureus</em> sortase A (SrtA) with an IC<sub>50</sub> of 73.43 μM, preventing bacterial adhesion to fibrinogen and subsequent biofilm formation. Fluorescence quenching assay and surface plasmon resonance analysis confirmed that DMY could directly bind to <em>S. aureus</em> SrtA. Notably, circular dichroism spectra demonstrated a conformational change in SrtA from α-helical to β-sheet structure upon DMY binding. Molecular dynamics simulation suggested that DMY bound to the catalytic pocket of <em>S. aureus</em> SrtA via hydrophobic interactions and hydrogen bonds. Furthermore, fluorescence microscopic observations further revealed that DMY attenuated the biofilm-related phenotype of SrtA by decreasing the anchoring of <em>S. aureus</em> protein A (SpA) onto cell wall. Importantly, pretreatment with 125 μg/mL DMY significantly reduced 1.14–1.75 log CFU/cm<sup>2</sup> of <em>S. aureus</em> adhered on eggshells. Overall, these findings highlight how specific targeting of SrtA by DMY inhibits the attachment stages of biofilm development in <em>S. aureus</em>, making it a promising candidate for a novel disinfectant against this pathogen in the food industry.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"426 ","pages":"Article 110925"},"PeriodicalIF":5.0,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142375432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Application of a novel lytic phage to control enterotoxigenic Escherichia coli in dairy food matrices 应用新型溶菌噬菌体控制乳制品基质中的肠毒性大肠埃希氏菌。

IF 5 1区农林科学 Q1 FOOD SCIENCE & TECHNOLOGY

International journal of food microbiology

Pub Date : 2024-09-27 DOI: 10.1016/j.ijfoodmicro.2024.110924

Madhvi Chahar , Anuj Rana , Vinay Kumar Gupta , Anu Singh , Namita Singh

A novel Escherichia coli phage designated as EC BD was isolated from cattle dung samples. Transmission electron microscopy demonstrated that the morphology of phage EC BD belongs to the family Myoviridae. The efficiency of plating (EOP) and scanning electron microscopy revealed the strong lytic activity of phage EC BD with a large burst size and a short latent period. Whole genome data analysis suggested that phage EC BD was inclined towards being completely lytic and revealed the absence of toxins, virulence and antibiotic resistance genes. Phylogenomic analysis of phage EC BD receptor binding proteins (RBPs) showed 74–100 % similarity with sixteen Enterobacter phages, representing their broad host range. The phage genome contains 262 ORFs, of which 107 displayed a unique pattern and additionally, the presence of a tRNA gene directed their fast replication and high stability. Comparative genome analysis suggested phage EC BD as a novel member of the genus Duplodnaviria and family Myoviridae. The efficiency of phage EC BD was determined in dairy food matrices (milk, cheese and paneer) artificially contaminated with enterotoxigenic E. coli strains ETEC H10407, ETEC K 12S and ETEC PB 176 with a significant reduction of 4.8, 6.0 and 5.3 log CFU/mL in milk and a substantial 4.9, 5.8 and 4.6 log CFU/mL reduction in cheese samples after 6 days at low storage temperature (4 °C); furthermore, within the similar conditions, paneer samples showed 4, 5.1 and 3.5 log CFU/mL reduction. EC BD phage treatment represents the complete eradication of three ETEC strains in liquid and semisolid dairy food matrices. This study suggested that phage EC BD might have potential as a biocontrol approach against ETEC foodborne infections.

从牛粪样本中分离出一种新型大肠杆菌噬菌体，命名为 EC BD。透射电子显微镜显示，EC BD噬菌体的形态属于肌病毒科。电镀效率（EOP）和扫描电子显微镜显示，EC BD噬菌体具有很强的溶菌活性，迸发量大，潜伏期短。全基因组数据分析表明，EC BD噬菌体倾向于完全溶菌，并发现它不含毒素、毒力和抗生素抗性基因。EC BD噬菌体受体结合蛋白（RBPs）的系统发生组分析表明，该噬菌体与16种肠杆菌噬菌体有74%-100%的相似性，代表了其广泛的宿主范围。噬菌体基因组包含 262 个 ORFs，其中 107 个显示出独特的模式，此外，tRNA 基因的存在使其具有快速复制和高度稳定性的特点。基因组比较分析表明，噬菌体 EC BD 是 Duplodnaviria 属和 Myoviridae 科的新成员。测定了 EC BD噬菌体在人工污染了肠毒性大肠杆菌 ETEC H10407、ETEC K 12S 和 ETEC PB 176 的乳制品基质（牛奶、奶酪和板面食品）中的效率，结果表明，ETEC H10407、ETEC K 12S 和 ETEC PB 176 能显著降低牛奶中 4.8、6.0 和 5.此外，在类似条件下，奶酪样品也分别减少了 4、5.1 和 3.5 log CFU/mL。EC BD噬菌体处理完全根除了液态和半固态乳制品基质中的三种ETEC菌株。这项研究表明，EC BD噬菌体有可能作为一种生物控制方法来对付食源性 ETEC 感染。

{"title":"Application of a novel lytic phage to control enterotoxigenic Escherichia coli in dairy food matrices","authors":"Madhvi Chahar , Anuj Rana , Vinay Kumar Gupta , Anu Singh , Namita Singh","doi":"10.1016/j.ijfoodmicro.2024.110924","DOIUrl":"10.1016/j.ijfoodmicro.2024.110924","url":null,"abstract":"<div><div>A novel <em>Escherichia coli</em> phage designated as EC BD was isolated from cattle dung samples. Transmission electron microscopy demonstrated that the morphology of phage EC BD belongs to the family Myoviridae. The efficiency of plating (EOP) and scanning electron microscopy revealed the strong lytic activity of phage EC BD with a large burst size and a short latent period. Whole genome data analysis suggested that phage EC BD was inclined towards being completely lytic and revealed the absence of toxins, virulence and antibiotic resistance genes. Phylogenomic analysis of phage EC BD receptor binding proteins (RBPs) showed 74–100 % similarity with sixteen Enterobacter phages, representing their broad host range. The phage genome contains 262 ORFs, of which 107 displayed a unique pattern and additionally, the presence of a tRNA gene directed their fast replication and high stability. Comparative genome analysis suggested phage EC BD as a novel member of the genus <em>Duplodnaviria</em> and family Myoviridae. The efficiency of phage EC BD was determined in dairy food matrices (milk, cheese and paneer) artificially contaminated with enterotoxigenic <em>E. coli</em> strains ETEC H10407, ETEC K 12S and ETEC PB 176 with a significant reduction of 4.8, 6.0 and 5.3 log CFU/mL in milk and a substantial 4.9, 5.8 and 4.6 log CFU/mL reduction in cheese samples after 6 days at low storage temperature (4 °C); furthermore, within the similar conditions, paneer samples showed 4, 5.1 and 3.5 log CFU/mL reduction. EC BD phage treatment represents the complete eradication of three ETEC strains in liquid and semisolid dairy food matrices. This study suggested that phage EC BD might have potential as a biocontrol approach against ETEC foodborne infections.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"426 ","pages":"Article 110924"},"PeriodicalIF":5.0,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142346239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Catalogue of surface proteins of Lactiplantibacillus plantarum strains of dairy and vegetable niches 植物乳杆菌（Lactiplantibacillus plantarum）乳制品和蔬菜菌株表面蛋白质目录。

IF 5 1区农林科学 Q1 FOOD SCIENCE & TECHNOLOGY

International journal of food microbiology

Pub Date : 2024-09-26 DOI: 10.1016/j.ijfoodmicro.2024.110922

Maria Fiorella Mazzeo , Alida Sorrentino , Stefano Morandi , Houssam Abouloifa , Abdeslam Asehraou , Milena Brasca , Rosa Anna Siciliano

Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) exhibits relevant probiotic and technological features and is widely used in food industries, improving flavour, texture and organoleptic properties of fermented products. Cell-surface proteins have a key role in the molecular mechanisms responsible for healthy effects, being the first actors in the bacteria - host interactions. Proteins present on the surface of four L. plantarum strains (two isolated from vegetable matrices and two from dairy products) were identified by proteomics with the aim to gain a comprehensive picture of differences in protein profiles potentially related to the habitat of origin and specific properties of the analyzed strains. Results highlighted a more diversified pattern of surface proteins in strains from vegetable matrices compared to those from dairy matrices (>500 proteins vs about 200 proteins, respectively). The four strains shared a core of 143 proteins, while 445 were specifically present in strains from vegetable matrices and 26 were peculiar of strains from dairy origin. Sortase A, involved in adhesion, and choloylglycine hydrolase (bile salt hydrolase) were detected only in strains from vegetable matrices. The peculiar molecular functions of identified proteins suggested that these strains, and in particular L. plantarum S61, could have a significant probiotic and biotechnological potential.

植物乳杆菌（原植物乳杆菌）具有相关的益生菌和技术特性，被广泛应用于食品工业，可改善发酵产品的风味、质地和感官特性。细胞表面蛋白质在产生健康效应的分子机制中起着关键作用，是细菌与宿主相互作用的首要参与者。通过蛋白质组学鉴定了四株植物酵母菌（两株从蔬菜基质中分离出来，两株从乳制品中分离出来）表面的蛋白质，目的是全面了解可能与原产地和所分析菌株的特定属性有关的蛋白质特征差异。结果表明，与来自乳制品基质的菌株相比，来自蔬菜基质的菌株表面蛋白质的模式更加多样化（分别为大于 500 个蛋白质和大约 200 个蛋白质）。四种菌株共有 143 个核心蛋白，其中 445 个特异性存在于来自蔬菜基质的菌株中，26 个为来自乳制品基质的菌株所特有。只有来自蔬菜基质的菌株中检测到了参与粘附的分类酶 A 和胆汁酰甘氨酸水解酶（胆盐水解酶）。已鉴定蛋白质的特殊分子功能表明，这些菌株，尤其是植物乳杆菌 S61，可能具有巨大的益生菌和生物技术潜力。

{"title":"Catalogue of surface proteins of Lactiplantibacillus plantarum strains of dairy and vegetable niches","authors":"Maria Fiorella Mazzeo , Alida Sorrentino , Stefano Morandi , Houssam Abouloifa , Abdeslam Asehraou , Milena Brasca , Rosa Anna Siciliano","doi":"10.1016/j.ijfoodmicro.2024.110922","DOIUrl":"10.1016/j.ijfoodmicro.2024.110922","url":null,"abstract":"<div><div><em>Lactiplantibacillus plantarum</em> (formerly <em>Lactobacillus plantarum</em>) exhibits relevant probiotic and technological features and is widely used in food industries, improving flavour, texture and organoleptic properties of fermented products. Cell-surface proteins have a key role in the molecular mechanisms responsible for healthy effects, being the first actors in the bacteria - host interactions. Proteins present on the surface of four <em>L. plantarum</em> strains (two isolated from vegetable matrices and two from dairy products) were identified by proteomics with the aim to gain a comprehensive picture of differences in protein profiles potentially related to the habitat of origin and specific properties of the analyzed strains. Results highlighted a more diversified pattern of surface proteins in strains from vegetable matrices compared to those from dairy matrices (>500 proteins <em>vs</em> about 200 proteins, respectively). The four strains shared a core of 143 proteins, while 445 were specifically present in strains from vegetable matrices and 26 were peculiar of strains from dairy origin. Sortase A, involved in adhesion, and choloylglycine hydrolase (bile salt hydrolase) were detected only in strains from vegetable matrices. The peculiar molecular functions of identified proteins suggested that these strains, and in particular <em>L. plantarum</em> S61, could have a significant probiotic and biotechnological potential.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"426 ","pages":"Article 110922"},"PeriodicalIF":5.0,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142346240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A novel high-level phenyllactic acid fungal producer, Kodamaea ohmeri w5 screened from fermented broad bean-chili-paste 从发酵蚕豆辣椒酱中筛选出一种新型高级苯乳酸生产真菌 Kodamaea ohmeri w5

IF 5 1区农林科学 Q1 FOOD SCIENCE & TECHNOLOGY

International journal of food microbiology

Pub Date : 2024-09-23 DOI: 10.1016/j.ijfoodmicro.2024.110923

Chi Zhao , Petri Penttinen , Lingzi Zhang , Ling Dong , Fengju Zhang , Decong Liao , Suyi Zhang , Zhihua Li , Xiaoping Zhang

Phenyllactic acid (PLA) is a broad-spectrum and efficient antimicrobial phenolic acid with potential applications in the food industry. Previous studies have demonstrated that fungi may be ideal producers of PLA. In this study, 15 fungi screened from Doubanjiang with the ability to produce PLA were first reported, including Wickerhamomyces anomalus, Candida etchellsii, Candida parasitosis, Pichia kudriavzevii, Pichia membranifaciens and Kodamaea ohmeri. Among them, K. ohmeri w5 had the highest PLA yield, producing up to 7160 mg/L PLA in shake flask fermentation with phenylalanine as substrate, which was more than ten times higher than the PLA produced by wild-type LAB under the similar conditions. In addition, K. ohmeri w5 was able to grow under extreme hypertonic conditions of 20 % NaCl (w/v) and 50 % glucose (w/v) as well as produce 57.12 ± 0.42 and 1609.22 ± 36.26 mg/L of PLA, respectively. Furthermore, the fermentation supernatant of K. ohmeri w5 demonstrated direct inhibitory effects against foodborne pathogenic microorganisms, Aspergillus flavus and Bacillus cereus. However, the inhibitory effect was weaker than that of the PLA standard at the same concentration. Further, 12,497,932 bp of w5 genome-wide information was obtained by sequencing and assembling. And its gene model was predicted based on transcriptomic evidence, which showed that a total of 7 genes related to PLA synthesis were identified in the w5 genome. Based on qRT-PCR, structure prediction, and molecular docking, a potentially key genetic resource from K. ohmeri w5 for PLA production was uncovered. The results will provide novel producers of PLA and its potential genetic resources.

苯乳酸（PLA）是一种广谱高效的抗菌酚酸，在食品工业中具有潜在的应用价值。以往的研究表明，真菌可能是聚乳酸的理想生产者。本研究首次报道了从豆瓣江筛选出的 15 种具有生产聚乳酸能力的真菌，包括 Wickerhamomyces anomalus、Candida etchellsii、Candida parasitosis、Pichia kudriavzevii、Pichia membranifaciens 和 Kodamaea ohmeri。其中，K. ohmeri w5 的聚乳酸产量最高，在以苯丙氨酸为底物的摇瓶发酵中，其聚乳酸产量高达 7160 mg/L，是野生型 LAB 在类似条件下聚乳酸产量的十倍以上。此外，K. ohmeri w5 还能在 20 % NaCl（体积分数）和 50 % 葡萄糖（体积分数）的极端高渗条件下生长，并分别产生 57.12 ± 0.42 和 1609.22 ± 36.26 mg/L 的聚乳酸。此外，K. ohmeri w5 的发酵上清液对食源性致病微生物黄曲霉和蜡样芽孢杆菌有直接抑制作用。不过，在相同浓度下，其抑制作用弱于聚乳酸标准品。此外，通过测序和组装，还获得了 12,497,932 bp 的 w5 全基因组信息。根据转录组证据预测了其基因模型，结果表明在 w5 基因组中共发现了 7 个与聚乳酸合成相关的基因。基于 qRT-PCR、结构预测和分子对接，从 K. ohmeri w5 中发现了生产聚乳酸的潜在关键基因资源。这些结果将为聚乳酸及其潜在遗传资源提供新的生产者。

{"title":"A novel high-level phenyllactic acid fungal producer, Kodamaea ohmeri w5 screened from fermented broad bean-chili-paste","authors":"Chi Zhao , Petri Penttinen , Lingzi Zhang , Ling Dong , Fengju Zhang , Decong Liao , Suyi Zhang , Zhihua Li , Xiaoping Zhang","doi":"10.1016/j.ijfoodmicro.2024.110923","DOIUrl":"10.1016/j.ijfoodmicro.2024.110923","url":null,"abstract":"<div><div>Phenyllactic acid (PLA) is a broad-spectrum and efficient antimicrobial phenolic acid with potential applications in the food industry. Previous studies have demonstrated that fungi may be ideal producers of PLA. In this study, 15 fungi screened from Doubanjiang with the ability to produce PLA were first reported, including <em>Wickerhamomyces anomalus</em>, <em>Candida etchellsii</em>, <em>Candida parasitosis</em>, <em>Pichia kudriavzevii</em>, <em>Pichia membranifaciens</em> and <em>Kodamaea ohmeri</em>. Among them, <em>K. ohmeri</em> w5 had the highest PLA yield, producing up to 7160 mg/L PLA in shake flask fermentation with phenylalanine as substrate, which was more than ten times higher than the PLA produced by wild-type LAB under the similar conditions. In addition, <em>K. ohmeri</em> w5 was able to grow under extreme hypertonic conditions of 20 % NaCl (<em>w</em>/<em>v</em>) and 50 % glucose (w/v) as well as produce 57.12 ± 0.42 and 1609.22 ± 36.26 mg/L of PLA, respectively. Furthermore, the fermentation supernatant of <em>K. ohmeri</em> w5 demonstrated direct inhibitory effects against foodborne pathogenic microorganisms, <em>Aspergillus flavus</em> and <em>Bacillus cereus</em>. However, the inhibitory effect was weaker than that of the PLA standard at the same concentration. Further, 12,497,932 bp of w5 genome-wide information was obtained by sequencing and assembling. And its gene model was predicted based on transcriptomic evidence, which showed that a total of 7 genes related to PLA synthesis were identified in the w5 genome. Based on qRT-PCR, structure prediction, and molecular docking, a potentially key genetic resource from <em>K. ohmeri</em> w5 for PLA production was uncovered. The results will provide novel producers of PLA and its potential genetic resources.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"426 ","pages":"Article 110923"},"PeriodicalIF":5.0,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0