Characterizing Environmental Background Microflora and Assessing Their Influence on <i>Listeria</i> Persistence in Dairy Processing Environment

<i>Listeria monocytogenes</i> (<i>Lm</i>) may persist in food processing environments (FPEs) alongside diverse background microflora. While microbial communities in FPEs can influence <i>Lm</i> survival, their role in supporting or suppressing its growth remains u...

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Main Authors: Vaishali Poswal, Sanjeev Anand, Brian Kraus
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/14/10/1694
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author Vaishali Poswal
Sanjeev Anand
Brian Kraus
author_facet Vaishali Poswal
Sanjeev Anand
Brian Kraus
author_sort Vaishali Poswal
collection DOAJ
description <i>Listeria monocytogenes</i> (<i>Lm</i>) may persist in food processing environments (FPEs) alongside diverse background microflora. While microbial communities in FPEs can influence <i>Lm</i> survival, their role in supporting or suppressing its growth remains unclear. This study aimed to characterize the microflora in floor swabs and air samples collected from a dairy processing facility across three seasons and assess their potential impact on the growth of a <i>Lm</i> test strain previously isolated from a dairy processing environment. A total of 167 environmental isolates, representing 30 bacterial genera, were identified. <i>Pseudomonas</i> was consistently prevalent across all sample types. Seasonal shifts in bacterial genera were observed, with differences in microbial composition and relative abundance between production lines with and without <i>Listeria innocua</i> occurrence. Microflora distribution appeared more influenced by environmental and operational factors than by spatial proximity. Co-culture growth assays revealed no competitive exclusion of the <i>Lm</i> test strain, and no zones of inhibition were observed in antimicrobial assays using cell-free extract and dialyzed cell-free extract from environmental isolates against <i>Lm</i>. These findings suggest that <i>Lm</i> could potentially establish itself within mixed microbial communities in dairy processing environments, emphasizing the complexity of microbial interactions in FPEs and their potential role in <i>Lm</i> persistence.
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spelling doaj-art-f9f25fb961784a63856594e15b4747eb2025-08-20T03:47:57ZengMDPI AGFoods2304-81582025-05-011410169410.3390/foods14101694Characterizing Environmental Background Microflora and Assessing Their Influence on <i>Listeria</i> Persistence in Dairy Processing EnvironmentVaishali Poswal0Sanjeev Anand1Brian Kraus2Department of Dairy and Food Science, South Dakota State University, Brookings, SD 57006, USADepartment of Dairy and Food Science, South Dakota State University, Brookings, SD 57006, USAWells Enterprises Inc., Le Mars, IA 51031, USA<i>Listeria monocytogenes</i> (<i>Lm</i>) may persist in food processing environments (FPEs) alongside diverse background microflora. While microbial communities in FPEs can influence <i>Lm</i> survival, their role in supporting or suppressing its growth remains unclear. This study aimed to characterize the microflora in floor swabs and air samples collected from a dairy processing facility across three seasons and assess their potential impact on the growth of a <i>Lm</i> test strain previously isolated from a dairy processing environment. A total of 167 environmental isolates, representing 30 bacterial genera, were identified. <i>Pseudomonas</i> was consistently prevalent across all sample types. Seasonal shifts in bacterial genera were observed, with differences in microbial composition and relative abundance between production lines with and without <i>Listeria innocua</i> occurrence. Microflora distribution appeared more influenced by environmental and operational factors than by spatial proximity. Co-culture growth assays revealed no competitive exclusion of the <i>Lm</i> test strain, and no zones of inhibition were observed in antimicrobial assays using cell-free extract and dialyzed cell-free extract from environmental isolates against <i>Lm</i>. These findings suggest that <i>Lm</i> could potentially establish itself within mixed microbial communities in dairy processing environments, emphasizing the complexity of microbial interactions in FPEs and their potential role in <i>Lm</i> persistence.https://www.mdpi.com/2304-8158/14/10/1694<i>Listeria monocytogenes</i>food processing environmentbiofilmfloor swabair samples
spellingShingle Vaishali Poswal
Sanjeev Anand
Brian Kraus
Characterizing Environmental Background Microflora and Assessing Their Influence on <i>Listeria</i> Persistence in Dairy Processing Environment
Foods
<i>Listeria monocytogenes</i>
food processing environment
biofilm
floor swab
air samples
title Characterizing Environmental Background Microflora and Assessing Their Influence on <i>Listeria</i> Persistence in Dairy Processing Environment
title_full Characterizing Environmental Background Microflora and Assessing Their Influence on <i>Listeria</i> Persistence in Dairy Processing Environment
title_fullStr Characterizing Environmental Background Microflora and Assessing Their Influence on <i>Listeria</i> Persistence in Dairy Processing Environment
title_full_unstemmed Characterizing Environmental Background Microflora and Assessing Their Influence on <i>Listeria</i> Persistence in Dairy Processing Environment
title_short Characterizing Environmental Background Microflora and Assessing Their Influence on <i>Listeria</i> Persistence in Dairy Processing Environment
title_sort characterizing environmental background microflora and assessing their influence on i listeria i persistence in dairy processing environment
topic <i>Listeria monocytogenes</i>
food processing environment
biofilm
floor swab
air samples
url https://www.mdpi.com/2304-8158/14/10/1694
work_keys_str_mv AT vaishaliposwal characterizingenvironmentalbackgroundmicrofloraandassessingtheirinfluenceonilisteriaipersistenceindairyprocessingenvironment
AT sanjeevanand characterizingenvironmentalbackgroundmicrofloraandassessingtheirinfluenceonilisteriaipersistenceindairyprocessingenvironment
AT briankraus characterizingenvironmentalbackgroundmicrofloraandassessingtheirinfluenceonilisteriaipersistenceindairyprocessingenvironment