Category Archives: Research

One in Five Chickens Contaminated by Pathogenic Bacteria – Which Report

UKPA 

One in five supermarket chickens is contaminated with the food poisoning bacteria campylobacter, an investigation has found.

The study of chicken samples from nine supermarkets by the Which? consumer group found 18% were contaminated with campylobacter and 17% were contaminated with listeria, with 4% containing levels of the latter classed as “high” by the Food Standards Agency (FSA). Salmonella was present in 1.5% of samples.

The watchdog tested 192 samples of whole chickens and chicken portions – standard, free range and organic and all reared in the UK – from Aldi, Asda, The Co-operative, Lidl, Marks & Spencer, Morrisons, Sainsbury’s, Tesco and Waitrose in March. Bacterial contamination was found in samples from each of the retailers.

The headline in the Sun Newspaper was a little more graphic!

The Telegraph had a view as well.

“Hypervirulent” Salmonella Research

EcoliBlog

Researchers at UC Santa Barbara, Michael Mahan and Douglas Heithoff, have published a new paper in the science journal, PLoS Pathogens, detailing their findings from a study of “hypervirulent” Salmonella bacteria.  Given the recently announced nationwide outbreak of Salmonella Bareilly associated with consumption of spicy tuna sushi, the publication of their paper could not be any more timely.

The paper, titled “Intraspecies Variation in the Emergence of Hyperinfectious Bacterial Strains in Nature,” focuses on the researchers’ efforts to seek out and locate hypervirulent strains that present a potential risk to food safety and the livestock industry.

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Withdrawn / Obsolete Standards: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  – Withdrawn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

Bad Bug New Release

FDA

This book is a great source of Microbiology Information and can be downloaded as a 264 page PDF.

The second edition of the Bad Bug Book3, published by the Center for Food Safety and Applied Nutrition, of the Food and Drug Administration (FDA), U.S. Department of Health and Human Services, provides current information about the major known agents that cause foodborne illness. The information provided in this handbook is abbreviated and general in nature, and is intended for practical use. It is not intended to be a comprehensive scientific or clinical reference. Each chapter in this book is about a pathogen – a bacterium, virus, or parasite – or a natural toxin that can contaminate food and cause illness. The book contains scientific and technical information about the major pathogens that cause these kinds of illnesses. A separate “consumer box” in each chapter provides non-technical information, in everyday language. The boxes describe plainly what can make you sick and, more important, how to prevent it.

Climate Change – Influences Pathogen Outbreaks?

Food Safety News 

To me this seems to be a reasonably logical assumption and this report attempts to back that up.

The transmission of foodborne pathogens may be impacted by the effects of climate change, according to a report released March 28 by the European Centre for Disease Prevention and Control.

Studying hundreds of peer-reviewed publications on six different food- and waterborne pathogens, the report’s authors observed 1,653 “key facts” that link the viability of those pathogens to a range of climatic variables such as air temperature, water temperature and precipitation. The pathogens under study included Campylobacter, Listeria, Salmonella, Norovirus, Cryptosporidium and non-cholera Vibrio.

Link to Report : Free Report

Norovirus Epidemiology Review

Cambridge Journals Online 

Food Safety Review

Norovirus – a bug that causes gastrointestinal illness – is responsible for 12 percent of all diarrheal disease worldwide and is estimated to cause 218,000 deaths among children under 5 each year. 
 
Now a clearer picture of how this virus spreads and where it originates is being drawn by a review published this week in Epidemiology & Infection.
 
Norovirus is derived from fecal matter, and can infect people via 4 routes: contaminated water, contaminated food, contaminated environmental surfaces or contact with an infected person. 
 
Researchers from Emory University and the University of Michigan looked at 902 Norovirus (NoV) outbreaks documented between 1993 and 2011, finding that most were associated with transmission through food or in a food service setting.
 
 

Study – Salmonella Survival in Mayonnaise

Ingenta Connect 

Mayonnaise made from contaminated eggs has been linked to outbreaks of Salmonella infections. This study was undertaken to determine the fate of salmonellae in home-style mayonnaise and acid solutions with or without chemical preservatives. Egg yolks were inoculated with different levels of a three-serotype (Typhimurium, Heidelberg, and Enteritidis [untypeable phage type]) mixture of Salmonella or a three-phage-type (4, 8, and 13) mixture of Salmonella Enteritidis. The inoculated yolks were used to make mayonnaise with 2, 3, or 4 teaspoons of a commercial wine vinegar or lemon juice. The mayonnaise was sampled for salmonellae over a 15-day period at 4°C, and negative samples were tested further by a three-tube most-probable-number assay. The same Salmonella mixtures were respectively inoculated into six acid solutions including wine vinegar, lemon juice, and acetic or citric solutions with or without chemical preservatives. The Salmonella populations of the Salmonella Enteritidis mixture were more persistent than those of the other Salmonella mixture in mayonnaise. Both Salmonella mixtures survived longer in mayonnaise made with vinegar than with lemon juice during storage at 4°C. In the acid solutions, however, the populations of the two Salmonella mixtures were not significantly different. The numbers of the two Salmonella mixtures in acetic or citric acid solutions with the preservatives were significantly lower than those in vinegar, lemon juice, and the solutions without the preservatives. Results suggest that Salmonella in contaminated egg yolks could survive the mayonnaise-making process. The inhibition of Salmonella by vinegar and lemon juice is due to the hurdle effect of organic acids and chemical preservatives.