A Few Pseudomonas Oligotypes Dominate in the Meat and Dairy Processing Environment.

Giuseppina Stellato,Danilo Ercolini,A Murat Eren,Maria De Angelis,Daniel R Utter,Andy Voorhis

doi:10.3389/fmicb.2017.00264

Abstract

The occurrence of bacteria in the food processing environments plays a key role in food contamination and development of spoilage. Species of the genus Pseudomonas are recognized as major food spoilers and the capability to actually determine spoilage can be species- as well as strain-dependent. In order to improve the taxonomic resolution of 16S rRNA gene amplicons, in this study we used oligotyping to investigate the diversity of Pseudomonas populations in meat and dairy processing environments. Sequences of the V1–V3 regions from previous studies were used, including environmental swabs and food samples from both meat and dairy processing plants. We showed that the most frequently found oligotypes belonged to Pseudomonas fragi and P. fluorescens, that the most abundant oligotypes co-occurred, and were shared between the meat and dairy datasets. All the oligotypes occurring in foods were also identified in the environmental samples of the corresponding plants, highlighting the important role of the environment as a source of strains for food contamination. Oligotypes of the same species showed different levels depending on food processing and type of sample, suggesting that different strains of the same species can have different adaptation efficiency, leading to resilient bacterial associations.

Highlights

The processing environment can be a fundamental source of food contamination across the food chains
A total of 15 Pseudomonas oligotypes were identified across the different batches of sequences and they were associated into meat and cheese datasets
Bacterial spoilage causes significant economic losses for the food industry and product contamination with psychrotrophic microorganisms is a particular concern for fresh foods

Summary

Introduction

The processing environment can be a fundamental source of food contamination across the food chains. Pseudomonas has been found as an abundant member of the microbiota in milk (De Jonghe et al, 2011; Marchand et al, 2012), beef (Ercolini et al, 2006, 2009), pork (Bruckner et al, 2012), chicken (Mellor et al, 2011), fish (Reynisson et al, 2008), and as a major contaminant of different surfaces (Bagge-Ravn et al, 2003; Brightwell et al, 2006; Licitra et al, 2007; Stellato et al, 2015b) Species such as Pseudomonas fragi, P. fluorescens, P. putida, P. gessardii, P. lundensis have been often isolated from spoiled foods and are currently recognized among the most threatening food spoilers (Ercolini et al, 2006, 2010; De Jonghe et al, 2011). Food spoiling potential is more than a species-specific trait

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Conclusion