Validation of the Thermo Scientific™ SureTect™ Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus PCR Assay for the Detection of Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus in Seafood Matrixes: AOAC Performance Tested MethodsSM 022301.

Background: The Thermo Scientific™ SureTect™ Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus PCR Assay method is a real-time PCR method for the multiplex detection of Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus in seafood.

Objective: The Thermo Scientific SureTect Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus Assay was evaluated for AOAC Performance Tested MethodsSM certification.

Method: Inclusivity/exclusivity, matrix, product consistency/stability, and robustness studies were conducted to assess the method's performance.

Evaluation of the Thermo Scientific SureTectTM Listeria Species PCR Assay in a Broad Range of Foods and Selected Environmental Surfaces: Pre-Collaborative and Collaborative Study, First Action 2021.06.

Background: The Thermo Scientific SureTect™ Listeria species PCR assay utilizes SolarisTM reagents for performing PCR for the rapid and specific detection of Listeria species in a broad range of foods and selected environmental surfaces.

Objective: To demonstrate reproducibility of the Thermo Scientific SureTect Listeria species PCR assay in a collaborative study using a challenging matrix, full-fat cottage cheese (25 g), to extend the scope of the method.

Methods: In the collaborative study, the candidate method was compared to the US Food and Drug Administration/Bacteriological Analytical Manual (FDA/BAM) Ch.

Evaluation of the Thermo ScientificTM SureTectTMListeria monocytogenes PCR Assay in a Broad Range of Foods and Selected Environmental Surfaces: Pre-Collaborative and Collaborative Study, First Action 2021.05.

Background: The Thermo Scientific™ SureTect™ Listeria monocytogenes PCR Assay uses Solaris reagents for performing PCR for the rapid and specific detection of Listeria monocytogenes in a broad range of foods and selected environmental surfaces.

Objective: To demonstrate reproducibility of the SureTect Listeria monocytogenes PCR Assay in a collaborative study using a challenging matrix, full-fat cottage cheese (25 g). To extend the scope of the method.

Validation of the Thermo Scientific SureTect™ Campylobacter jejuni, C. coli, and C. lari PCR Kit for the Detection of Campylobacter jejuni, C. coli, and C. lari in Raw Poultry and Ready-to-Cook Poultry Products: AOAC Performance Tested MethodSM 012101.

Background: The Thermo Scientific SureTect™ Campylobacter jejuni, C. coli, and C. lari PCR Kit is a real-time PCR assay for the detection and differentiation of C.

Validation of the Thermo Scientific™ SureTect™Staphylococcus aureus PCR Assay for the Detection of Staphylococcus aureus in Dairy Matrixes: AOAC Performance Tested MethodSM 052101.

Background: The Thermo Scientific™ SureTect™Staphylococcus aureus PCR Assay is a real-time PCR assay for the detection of Staphylococcus aureus in dairy samples.

Objective: The Thermo Scientific SureTect Staphylococcus aureus PCR Assay was evaluated for AOAC Performance Tested MethodSM certification.

Methods: Inclusivity/exclusivity, matrix studies, product consistency and stability, and robustness testing were conducted to assess the method's performance.

Validation of the Thermo Scientific SureTect™ Escherichia coli O157:H7 and STEC Screening PCR Assay and SureTect™ Escherichia coli STEC Identification PCR Assay for the Detection of Escherichia coli O157:H7 and the Escherichia coli STEC Serotypes (O26, O45, O103, O111, O121, O145) from Fresh Raw Spinach, Fresh Baby Leaves, Fresh Cut Tomatoes, Frozen Raw Beef, Raw Beef Trim, and Beef Carcass Sponges: AOAC Performance Tested MethodSM 012102.

Background: The Thermo Scientific SureTect™ Escherichia coli O157:H7 and STEC Screening PCR Assay and SureTect Escherichia coli STEC Identification PCR Assay are real-time PCR kits for the rapid detection of E. coli O157:H7 and non-E. coli O157 Shiga toxin-producing E.

Evaluation of the Thermo Scientific SureTect Salmonella Species PCR Assay in a Broad Range of Foods and Select Environmental Surfaces: Pre-Collaborative and Collaborative Study: First Action 2021.02.

Background: The Thermo Scientific™ SureTect™ Salmonella species PCR Assay utilizes Solaris™ reagents for performing PCR for the rapid and specific detection of Salmonella species in a broad range of foods and select environmental surfaces.

Objective: The aims were to demonstrate the reproducibility of the Thermo Scientific SureTect Salmonella species PCR Assay in a collaborative study using a challenging matrix, cocoa powder, and to extend the scope of the method.

Method: In the collaborative study, the candidate method was compared to the US Food and Drug Administration (FDA) Bacteriological Analytical Manual (BAM) Chapter 5 Salmonella reference method.

Validation of the Thermo Scientific™ SARS-CoV-2 RT-PCR Detection Workflow for the Detection of SARS-CoV-2 from Stainless-Steel Environmental Surface Swabs: AOAC Performance Tested MethodSM 012103.

Background: The Thermo Scientific™ SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR) Detection Workflow, packaged with Applied Biosystems™ TaqMan™ 2019-nCoV Assay Kit v1 targets three different SARS-CoV-2 genomic regions in a single RT-PCR reaction.

Objective: To validate the Thermo Scientific SARS-CoV-2 RT-PCR Workflow, for the detection of SARS-CoV-2 virus on stainless-steel surfaces as part of the AOAC Performance Tested MethodSM Emergency Response Validation program.

Method: The Applied Biosystems TaqMan 2019-nCoV Assay Kit v1, as part of the Thermo Scientific SARS-CoV-2 RT-PCR Workflow, was evaluated for specificity using in silico analysis of 15 764 SARS-CoV-2 sequences and 65 exclusivity organisms.

Confirmation and Identification of spp., spp., and Other Gram-Negative Organisms by the Bruker MALDI Biotyper Method: Collaborative Study Method Extension to Include Species, Revised First Action 2017.09.

The Bruker MALDI Biotyper method utilizes matrix-assisted laser desorption/ionization time-of-flight MS for the rapid and accurate identification and confirmation of Gram-negative bacteria from select media types. The alternative method was evaluated in a method extension study of AOAC INTERNATIONAL 2017.09 using nonselective and selective agars to identify spp.

Confirmation and Identification of spp. and Other Gram-Positive Organisms by the Bruker MALDI Biotyper Method: Collaborative Study, First Action 2017.10.

The Bruker MALDI Biotyper® method utilizes matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS for the rapid and accurate confirmation and identification of Gram-positive bacteria from select media types. This alternative method was evaluated using nonselective and selective agar plates to identify and confirm Listeria monocytogenes, Listeria species, and select Gram-positive bacteria. Results obtained by the Bruker MALDI Biotyper were compared with the traditional biochemical methods as prescribed in the appropriate reference method standards.

Confirmation and Identification of spp., spp., and Other Gram-Negative Organisms by the Bruker MALDI Biotyper Method: Collaborative Study, First Action 2017.09.

The Bruker MALDI Biotyper® method utilizes matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS for the rapid and accurate identification and confirmation of Gram-negative bacteria from select media types. The alternative method was evaluated using nonselective and selective agars to identify Cronobacter spp., Salmonella spp.

mRNA biomarkers selection based on Partial Least Square algorithm in order to further predict Bacillus weihenstephanensis acid resistance.

In order to integrate omics data to quantitative microbiological risk assessment in foods, gene expressions may serve as bacterial behaviour biomarkers. In this study an integrative approach encompassing predictive modelling and mRNAs quantifications, was followed to select molecular biomarkers to further predict the acid resistance of Bacillus weihenstephanensis. A multivariate analysis was performed to correlate the acid bacterial resistance and the gene expression of vegetative cells with or without exposure to stressing conditions.

Comparison of three Bacillus amyloliquefaciens strains growth behaviour and evaluation of the spoilage risk during bread shelf-life.

This study aims at the characterisation of growth behaviour of three strains of Bacillus amyloliquefaciens, isolated from ropy bread (ATCC8473), wheat grain (ISPA-S109.3) and semolina (ISPA-N9.1) to estimate rope spoilage risk in pan bread during shelf-life using the Sym'Previus tool.

Modeling the recovery of heat-treated Bacillus licheniformis Ad978 and Bacillus weihenstephanensis KBAB4 spores at suboptimal temperature and pH using growth limits.

The apparent heat resistance of spores of Bacillus weihenstephanensis and Bacillus licheniformis was measured and expressed as the time to first decimal reduction (δ value) at a given recovery temperature and pH. Spores of B. weihenstephanensis were produced at 30°C and 12°C, and spores of B.

Evolution of microbiological analytical methods for dairy industry needs.

Traditionally, culture-based methods have been used to enumerate microbial populations in dairy products. Recent developments in molecular methods now enable faster and more sensitive analyses than classical microbiology procedures. These molecular tools allow a detailed characterization of cell physiological states and bacterial fitness and thus, offer new perspectives to integration of microbial physiology monitoring to improve industrial processes.

Bacillus cereus cell response upon exposure to acid environment: toward the identification of potential biomarkers.

Microorganisms are able to adapt to different environments and evolve rapidly, allowing them to cope with their new environments. Such adaptive response and associated protections toward other lethal stresses, is a crucial survival strategy for a wide spectrum of microorganisms, including food spoilage bacteria, pathogens, and organisms used in functional food applications. The growing demand for minimal processed food yields to an increasing use of combination of hurdles or mild preservation factors in the food industry.

Sensitivity of Bacillus weihenstephanensis to acidic changes of the medium is not dependant on physiological state.

This study aims to quantify the effect of salt and acid preliminary exposure on acid resistance of vegetative cells of Bacillus weihenstephanensis. The psychrotolerant strain KBAB4 was cultured until the mid-exponentially phase (i) in BHI, (ii) in BHI supplemented with 2.5% salt or (iii) in BHI acidified at pH 5.

Prediction of Bacillus weihenstephanensis acid resistance: the use of gene expression patterns to select potential biomarkers.

Exposure to mild stress conditions can activate stress adaptation mechanisms and provide cross-resistance towards otherwise lethal stresses. In this study, an approach was followed to select molecular biomarkers (quantitative gene expressions) to predict induced acid resistance after exposure to various mild stresses, i.e.

An integrative approach to identify Bacillus weihenstephanensis resistance biomarkers using gene expression quantification throughout acid inactivation.

The aim of this study was to define an integrative approach to identify resistance biomarkers using gene expression quantification and mathematical modelling. Mid-exponentially growing cells were transferred into acid conditions (BHI, pH 4.6) to obtain inactivation kinetics, performed in triplicate.

Tracking spore-forming bacteria in food: from natural biodiversity to selection by processes.

Sporeforming bacteria are ubiquitous in the environment and exhibit a wide range of diversity leading to their natural prevalence in foodstuff. The state of the art of sporeformer prevalence in ingredients and food was investigated using a multiparametric PCR-based tool that enables simultaneous detection and identification of various genera and species mostly encountered in food, i.e.

Polyphasic approach for quantitative analysis of obligately heterofermentative Lactobacillus species in cheese.

Obligately heterofermentative lactobacilli (OHL) present in cheese during ripening can influence the flavour and texture of the final product. In order to better evaluate, follow and control this population, there is a current need for easy-to-use tools. In this study, a culture-dependent quantitative method (ABEV medium) was set up for direct and selective enumeration of total OHL from cheese, and a culture-independent method based on specific real time PCR (qPCR) assays was developed to target Lactobacillus fermentum and Lactobacillus parabuchneri individual species.

Reverse transcription quantitative PCR revealed persistency of thermophilic lactic acid bacteria metabolic activity until the end of the ripening of Emmental cheese.

For Emmental manufacture two kinds of adjunct culture are added: (i) thermophilic lactic acid bacteria (starters) such as Lactobacillus helveticus (LH), and Streptococcus thermophilus (ST) growing the first day of the manufacture and (ii) ripening culture. ST and LH have a key role in curd acidification and proteolysis at the beginning of the manufacture but are considered to be lyzed for a great part of them at the ripening step. The aim of this work was to assess the metabolic activity of these bacteria throughout manufacture and ripening.

Recent advances in quantitative PCR (qPCR) applications in food microbiology.

Molecular methods are being increasingly applied to detect, quantify and study microbial populations in food or during food processes. Among these methods, PCR-based techniques have been the subject of considerable focus and ISO guidelines have been established for the detection of food-borne pathogens. More particularly, real-time quantitative PCR (qPCR) is considered as a method of choice for the detection and quantification of microorganisms.

A multiparametric PCR-based tool for fast detection and identification of spore-forming bacteria in food.

The presence of psychrotrophic or highly thermoresistant spore-forming bacteria in food and feedstuff responsible for food poisoning and spoilage raises major safety and economical issues. The aim of this study was to evaluate the performances of a ready-to-use PCR assay (alternative method) in comparison with the standard microbiological plating method regarding spore-forming bacteria detection in food samples. An overnight sample enrichment was selected to increase sporeformer diversity recovery, spore germination, bacterial growth and favour DNA extraction.