Oil-in-water emulsion and acid concentrations impact Bacillus weihenstephanensis KBAB4 growth and culturability

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

International journal of food microbiology Pub Date : 2025-02-27 DOI:10.1016/j.ijfoodmicro.2025.111132

Agathe Dutoit, Clément Trunet, Nicolas Decourcelle, Anne-Gabrielle Mathot, Louis Coroller

{"title":"Oil-in-water emulsion and acid concentrations impact Bacillus weihenstephanensis KBAB4 growth and culturability","authors":"Agathe Dutoit, Clément Trunet, Nicolas Decourcelle, Anne-Gabrielle Mathot, Louis Coroller","doi":"10.1016/j.ijfoodmicro.2025.111132","DOIUrl":null,"url":null,"abstract":"<div><div>Organic acids have long been used to limit microbial growth and preserve food products from spoilage and pathogens. However, the food complexity can affect the efficiency of preservatives in inhibiting bacterial growth. The inhibitory activity of acetic, lactic, caprylic and lauric acid in nutrient broth and in a model food system, i.e. an oil-in-water (O/W) emulsion at two pH levels, were compared using the plate count method.</div><div>The fate of <em>B. weihenstephanensis</em> KBAB4 cells incubated in O/W emulsions revealed a loss of culturability on Brain Heart Infusion agar (BHI agar) medium, occurring at different times according to the tested conditions. Cell viability in O/W emulsion was assessed through flow cytometry measurements which confirmed that a large majority of cells possessed an intact membrane, despite only 3 % being able to recover on BHI agar. Decreasing the pH of the emulsions delayed the time at which cells lost their culturability as well as the time at which it was restored. Using acetic, caprylic and lauric acid in the emulsion impacted strain recovery on BHI agar whereas using lactic acid enhanced the cell recovery from the emulsion exposure, on BHI agar surface.</div><div>The culturability of <em>B. weihenstephanensis</em> KBAB4 cells incubated in an O/W emulsion without acid has been restored using other recovery media, highlighting ROS involvement and limited strain catalase activity in the recovery ability. This study put in evidence the susceptibility of this strain to oxidative stress and challenges the use of given media for enumerating spore-forming bacteria in food and other complex matrices.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"434 ","pages":"Article 111132"},"PeriodicalIF":5.0000,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International journal of food microbiology","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0168160525000777","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"FOOD SCIENCE & TECHNOLOGY","Score":null,"Total":0}

引用次数: 0

Abstract

Organic acids have long been used to limit microbial growth and preserve food products from spoilage and pathogens. However, the food complexity can affect the efficiency of preservatives in inhibiting bacterial growth. The inhibitory activity of acetic, lactic, caprylic and lauric acid in nutrient broth and in a model food system, i.e. an oil-in-water (O/W) emulsion at two pH levels, were compared using the plate count method.

The fate of B. weihenstephanensis KBAB4 cells incubated in O/W emulsions revealed a loss of culturability on Brain Heart Infusion agar (BHI agar) medium, occurring at different times according to the tested conditions. Cell viability in O/W emulsion was assessed through flow cytometry measurements which confirmed that a large majority of cells possessed an intact membrane, despite only 3 % being able to recover on BHI agar. Decreasing the pH of the emulsions delayed the time at which cells lost their culturability as well as the time at which it was restored. Using acetic, caprylic and lauric acid in the emulsion impacted strain recovery on BHI agar whereas using lactic acid enhanced the cell recovery from the emulsion exposure, on BHI agar surface.

The culturability of B. weihenstephanensis KBAB4 cells incubated in an O/W emulsion without acid has been restored using other recovery media, highlighting ROS involvement and limited strain catalase activity in the recovery ability. This study put in evidence the susceptibility of this strain to oxidative stress and challenges the use of given media for enumerating spore-forming bacteria in food and other complex matrices.

查看原文本刊更多论文

水包油乳剂和酸浓度对威氏芽孢杆菌KBAB4生长和培养能力的影响

有机酸长期以来一直被用来限制微生物的生长，保护食品免受腐败和病原体的侵害。然而，食品的复杂性会影响防腐剂抑制细菌生长的效率。采用平板计数法比较了营养肉汤和模拟食品体系（即水包油（O/W）乳化液）在两种pH水平下对乙酸、乳酸、癸酸和月桂酸的抑制活性。在O/W乳剂中培养的B. weihenstephanensis KBAB4细胞的命运显示，在脑心灌注琼脂（BHI琼脂）培养基上，根据测试条件的不同，在不同的时间发生可培养性丧失。通过流式细胞术测量来评估O/W乳液中的细胞活力，证实绝大多数细胞具有完整的膜，尽管只有3%能够在BHI琼脂上恢复。降低乳剂的pH值可以延缓细胞丧失可培养性的时间，也可以延缓细胞恢复可培养性的时间。在乳剂中使用乙酸、辛酸和月桂酸对BHI琼脂上的菌株恢复有影响，而使用乳酸对BHI琼脂表面的细胞恢复有促进作用。在无酸的O/W乳液中培养的B. weihenstephanensis KBAB4细胞在其他恢复培养基中恢复了培养能力，突出了ROS的参与和菌株过氧化氢酶活性的限制。这项研究证明了该菌株对氧化应激的敏感性，并挑战了在食物和其他复杂基质中使用给定培养基来枚举孢子形成细菌的方法。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

International journal of food microbiology 工程技术-食品科技

CiteScore

10.40

自引率

5.60%

发文量

322

审稿时长

65 days

期刊介绍： The International Journal of Food Microbiology publishes papers dealing with all aspects of food microbiology. Articles must present information that is novel, has high impact and interest, and is of high scientific quality. They should provide scientific or technological advancement in the specific field of interest of the journal and enhance its strong international reputation. Preliminary or confirmatory results as well as contributions not strictly related to food microbiology will not be considered for publication.