Category Archives: ISO Standards

Research – Verification of a Rapid Analytical Method for the Qualitative Detection of Listeria spp. and Listeria monocytogenes by a Real-Time PCR Assay according to EN UNI ISO 16140-3:2021

MDPI

Abstract

Microbial contamination and foodborne infections are a significant global public health concern. For this reason, the detection, monitoring, and characterization of pathogens represent a significant challenge in quality control settings. Standard approaches, such as culture methods and biochemical tests, are known to be very time-consuming and intensive. Conversely, molecular technologies based on the genomic identification of bacteria are quick and low-cost. Listeria monocytogenes is an opportunistic pathogen and a major concern especially in food industries. It is important to understand and implement multiple quality control measures to control Listeria infection risk and prevent the contamination of products. Standardized detection and confirmation tests such as the API Listeria test, MALDI-TOF MS, and PCR analysis are available. The aim of our work is to provide a specific molecular method, designed according to the EN UNI ISO 16140-3:2021, for the specific detection, monitoring, and characterization of Listeria spp. and Listeria monocytogenes contamination. The verification of this new rapid approach by real-time PCR (qPCR) overcomes the limitations of culture-based techniques, meeting all the verification criteria required by ISO guidelines, including implementation and item confirmation. This system offers a powerful approach to the real-time assessment of food safety, useful for industry self-monitoring and regulatory inspection.

UK – LABhelp – Independent Advisors with Over 20 years of Combined Experience of 3rd Party Auditing to ISO17025

LABhelp LH

We are home based UK Microbiology & Chemistry Laboratory Technical & Quality Advisors providing bespoke laboratory services which can be both site based and off-site. Off-site support services include, but are not limited to, procedure & method review, results interpretation, external proficiency interpretation. On-site services include hands-on training in laboratory bench practices & best practice techniques, procedure & record streamlining, internal auditing & method witnessing.

 

BS – ISO Standards Updates for 2012

British Standards Update(ISO/EN) 2012

Withdrawn / Obsolete Standards:

BS 5763-13, 1998 :   Methods for microbiological examination of food and animal feeding stuffs — Enumeration of Escherichia coli. Colony-count.  – Withdrawn

BS 4285 – 5.2, 1989 :  Microbiological examination for dairy purposes. Ancillary methods — Methylene blue reduction test for cream and ice cream. – Obsolete

 Newly Published Standards:

BS EN ISO 6887-4 : 2003 AMD 1-  2011 

Specific rules for the preparation of products other than milk and milk products, meat and meat products, and fish and fishery products.

See update document.

 BS EN ISO 16140 : 2003 AMD 1 – 2011

Microbiology of food and animal feeding stuffs — Protocol for the validation of alternative methods.

 BS EN ISO 22119 : 2011

Microbiology of food and animal feeding stuffs — Realtime polymerase chain reaction

(PCR) for the detection of foodborne pathogens — General requirements and definitions.

 BS EN ISO 22118 : 2011

Microbiology of food and animal feeding stuffs — Polymerase chain reaction (PCR) for the detection and quantification of food-borne pathogens — Performance characteristics.

 BS EN ISO 11133 – 2 : 2003 AMD 1 : 2011

Microbiology of food and animal feeding stuffs — Guidelines on preparation and production of culture media — Part 2: Practical guidelines on performance testing of culture media

See update document.

New Work Item Procedures

BS EN ISO NWIP 16649-3

Microbiology of food and animal feed — Enumeration of β-glucuronidase positive Escherichia coli — Part 3: Most probable number technique using 5-bromo-4-chloro-3-indolyl-β-D-glucuronide

 Disclaimer modified to state that only Milk and Milk product has not been validated for this method.

ISO 7251 and 6887-5 added to normative references.

Section 4 Principle now covers both Detection ( added ) as well as Enumeration.

Section 5 Media performance testing now states WDCM Culture references.

Section 9 now includes detection procedure as well as enumeration procedure.

Section 10 now gives guidance on reporting of Detection results.

 NWIP ISO/TR 6579-3

Microbiology of food and animal feed – Horizontal method for the detection, enumeration and serotyping of Salmonella – Part 3 Guidelines for serotyping of Salmonella spp.

 NWIP ISO 4833 -2

Microbiology of food and animal feed – Horizontal method for the enumeration of Microorganisms – Part 2: Colony count at 30 degrees C by the surface plating technique (ISO/DIS 4833-2:2012)

 NWIP ISO / PDTS

Microbiology of food and animal feed — Polymerase chain reaction (PCR) for the detection of food-borne pathogens — Detection of botulinum type A, B, E and F neurotoxin producing Clostridia.

 NWIP ISO/TS 11290-1 Horizontal method for the detection and enumeration of Listeria monocytogenes and other Listeria species —Part 1 Detection method

Proposal to reduce Fraser Broth enrichment to 24hrs

Proposal to confirm only one colony at a time until correct identification is achieved.

Use of Haemolysis, VP, Rhamnose and Xylose only for L. mono identification. Optional Gram stain and CAMP test

NWIP ISO/TS 11290-2  Horizontal method for the detection and enumeration of Listeria monocytogenes and other Listeria species — Part 2 Enumeration method.

 Proposal to remove resuscitation stage

Proposal to use 1 x 140mm ALOA or 3 x 90mm ALOA plates

Proposal to incubate at 37C for 24 ± 3 hrs instead of 18 – 24hrs ( repeat for further 24 hrs )

Proposal for countable range on 140 mm plates at 235 cfu.

Proposal to use any non selective agar for colony streaking for confirmation purposes

( Blood agar, Nutrient agar etc )

Proposal to remove gram stain from confirmation and optional Catalase test

Use of Haemolysis, VP, Rhamnose and Xylose only for L. mono identification.

Expression of results now cross referenced to ISO 7218

NWIP  ISO 7218   Microbiology of food and animal feeding stuffs – General requirements and guidance for microbiological examinations – Amendment 1 (ISO 7218:2007/DAM :2011)

World Data Center for Microoganisms-Reference Strain Catalogue

WDCM

This catalogue was produced to enable broader and easier access to the reference strains listed by the ISO TC 34 SC 9 Joint Working Group 5 and by the Working Party on Culture Media of the International Committee on Food Microbiology and Hygiene (ICFMH-WPCM) in their publication Handbook of Culture Media for Food and Water Microbiology. It fulfils a need expressed by these bodies for a unique system of identifiers for strains recommended for use in quality assurance.
 
UKAS in the UK will in time be expecting the use of WDCM Reference numbers in methods when the use of reference strains are quoted. This is to remove commercial bias from different culture collection material reference numbers