Category Archives: Listeria

Research – ECDC TECHNICAL REPORT Proficiency test for Listeria monocytogenes whole genome assembly

ECDC ecdclogo

Executive summary
Within its mission to operate EU surveillance networks, ECDC supports the integration of whole genome sequencing (WGS) data into surveillance and multi-country outbreak investigations of foodborne diseases including listeriosis as one of the priority diseases. To evaluate the inter-laboratory reproducibility and portability of Listeria monocytogenes genome assemblies, ECDC organised a proficiency test for national public health reference laboratories with WGS typing capabilities in the EU/EEA, as well as EFSA and the EU Reference Laboratory for L. monocytogenes.
This report presents the results of the proficiency test. Each participant received a total of 15 sets of raw sequence reads, which were to be assembled by one or more pipelines of their choice. The resulting assemblies were then compared to the reference assembly generated by ECDC on several quality metrics. There were 16 participants, submitting results for 29 pipelines. Twelve participants, including 10 of the 14 participating public health reference laboratories, had at least one concordant pipeline for Illumina reads. The other participants were provided with individual feedback on possibilities to improve their pipeline(s). Participants with a concordant pipeline are recommended to use that for their own analyses as well as for any sharing of assemblies with other organisations including ECDC. For EU-level surveillance purposes ECDC will only accept assemblies generated with a concordant pipeline. Any new pipelines or updates to existing pipelines should go through the same proficiency testing before being used for sharing data with ECDC. For outbreak investigation purposes when more detailed analysis can be needed, raw sequence reads are proposed to be shared instead of or in addition to assemblies for isolates included in the cluster. For Ion Torrent reads, it was not possible to establish concordance. ECDC suggests that any countries producing
these reads share not only the reads with other organisations but also the extracted allele sequences for at least the core genome in the form of a fasta file. This was shown to produce acceptable results and allows other organisations, including ECDC, to perform their allele calling as with any regular assembly. It was also found that the assembly process can be used to remove low-level contamination. Conversely, low-level
contamination can give rise to much longer assembly lengths than the expected length due to the presence of a
large number of very small contigs with very low quality. It is recommended that assembly pipelines include
removal of such small and unreliable contigs, ideally in a way that still alerts the user to the likely presence of
low-level contamination.
EU laboratories that have installed a new or updated pipeline are welcome to have its concordance assessed by
ECDC at any time.

 

Canada – Updated Food Recall Warning – Dom Reserve brand Atlantic Salmon Strips (Hot Smoked) Cracked Black Pepper recalled due to Listeria monocytogenes

CFIA

Recall details

Ottawa, May 17, 2019 – The food recall warning issued on May 14, 2019 has been updated to include additional product information. This additional information was identified during the Canadian Food Inspection Agency’s (CFIA) food safety investigation.

DOM International Limited is recalling Dom Reserve brand Atlantic Salmon Strips (Hot Smoked) Cracked Black Pepper from the marketplace due to possible Listeria monocytogenes contamination. Consumers should not consume the recalled product described below.

Recalled products

Brand Name Common Name Size Code(s) on Product UPC
Dom Reserve Atlantic Salmon Strips
(Hot Smoked) Cracked Black Pepper
150 g 001996, 002176, 002325, 002371, 02533
All Best Before dates
7 72945 11150 8

Research – Lab work in South Africa’s Listeria outbreak was ‘remarkable’

Food Safety News

Researchers have described how a laboratory handled increased demand during the 2017-2018 listeriosis outbreak in South Africa.

Whole genome sequencing (WGS) and epidemiological data were used to determine the source of the outbreak as ready-to-eat processed meat manufactured by Enterprise Foods.

A total of 1,060 cases were reported from January 2017 to July 2018 and 216 people died.

The largest ever reported outbreak of listeriosis included an alert in mid-June 2017, a peak in mid-November 2017, and identification of the outbreak source in mid-February 2018.

“This eight-month timeline was rather remarkable, considering the large number of cases involved and the limited capacity and resources available for foodborne disease outbreak investigations in South Africa,” according to researchers.

The study is published in the Foodborne Pathogens and Disease journal

RASFF Alert – Listeria monocytogenes – Chilled Cooked Smoked Duck Fillet

RASFF-Logo

RASFF – Listeria monocytogenes (<10 CFU/g) in chilled cooked smoked duck fillet from France in France

 

Canada – Updated Food Recall Warning – Dom Reserve brand Atlantic Salmon Strips (Hot Smoked) Cracked Black Pepper recalled due to Listeria monocytogenes

CFIA

Dom Reserve: Atlantic Salmon Strips: 150 g

Recall details

Ottawa, May 14, 2019 – The food recall warning issued on May 5, 2019 has been updated to include additional product information. This additional information was identified during the Canadian Food Inspection Agency’s (CFIA) food safety investigation.

DOM International Limited is recalling Dom Reserve brand Atlantic Salmon Strips (Hot Smoked) Cracked Black Pepper from the marketplace due to possible Listeria monocytogenes contamination. Consumers should not consume the recalled product described below.

Recalled products

Brand Name Common Name Size Code(s) on Product UPC
Dom Reserve Atlantic Salmon Strips (Hot Smoked) Cracked Black Pepper 150 g 001851
All Best Before dates
7 72945 11150 8

Research – Utilizing kitchen steamers to inactivate Listeria monocytogenes and Salmonella enterica on whole cantaloupe melons

Wiley Online

 

Abstract

Cantaloupes contaminated with Listeria and Salmonella have caused large scale of foodborne illness outbreaks in recent years. Prior research has shown that heat treatment can be used to reduce microbial contaminates on fruit surfaces. However, no study has evaluated the use of kitchen steamers for inactivating foodborne pathogens on cantaloupes. The purpose of this study was to test the sanitization efficacy of three models of electrical kitchen steamers (steamer‐A, ‐B, and ‐C) for eliminating foodborne pathogens on cantaloupe surfaces. Fresh cantaloupes were spot‐inoculated with Listeria monocytogens or Salmonella enterica and kept at 4 or 22 °C for a day before steam treatment for ≤100 s. Test results show that the surface of nonrefrigerated cantaloupes can be decontaminated (with ≥5.0 log reduction) within 60 s using any of the tested steamers. For refrigerated fruits (4 °C), however, only two steamers (steamer‐B and ‐C) decontaminated the cantaloupes within 60 s and they were unable to render the pathogens undetected in enriched samples. Salmonella was more susceptible than Listeria to steam treatment. In conclusion, electrical kitchen steamers can be utilized by consumers to sanitize whole cantaloupes prior to consumption. However, fruit temperature and steamer selection can influence the heating time required for surface sanitization.

Practical applications

Melons with netted rind surfaces, such as cantaloupes, likely have caused more outbreaks because their surface shelters pathogens from being eliminated by conventional washing and sanitization. As whole melons marketed at retail stores typically are not treated due to shelf‐life considerations, the safety of untreated melons can be of concern to consumers, especially among at‐risk populations. This study focused on the evaluation of the use of commercially available kitchen steamers in eliminating foodborne pathogens on cantaloupe surfaces. This study showed that kitchen steamers can be utilized to sanitize whole cantaloupes and also at household level, be a highly beneficial for the average concerned consumer to reduce the risk of pathogens on produce before consumption.

USA – Salmon recalled over Listeria monocytogenes

Food Poison Journal

Listeria kswfoodworld food safety food poisoning

Image CDC

 

Biltmore smoked sockeye salmon is being recalled by Seven Seas International LLC USA St. Petersburg, FL because Listeria monocytogenes may be present in some product. This was discovered through routine regulatory testing conducted by the Florida Department of Agriculture and Consumer Services. Consumers who have purchased this product are being advised not to consume it and return it to the store where it was originally purchased for a full refund.