Switch Language

Research Note: Phage protects smoked salmon, naturally contaminated with Listeria monocytogenes

Research Note: Phage protects smoked salmon, naturally contaminated with Listeria monocytogenes

April 12, 2019

Objective

Study the efficacy of phages applied on smoked salmon that have been naturally contaminated with Listeria monocytogenes.

Protocol

A total of 48 smoked salmon slices were divided in three parts:

  • Part A was analyzed at day zero (D0) in order to detect the presence/absence of Listeria monocytogenes (control without phages D0)
  • Part B was treated with Phageguard Listex at 109 PFU/cm2. This part was analyzed for Listeria at the end of the shelf-life.

Part C was analyzed at the end of the shelf life in order to detect the presence/absence of Listeria monocytogenes (control without phages D28).

For the slices were part A was positive for Listeria monocytogenes, parts B and C were vacuum packaged and stored for 10 days at 4°C and for 18 days at 8°C. Enrichment of L. monocytogenes was performed according to the validated AFNOR Aloa One Day method and numerations were done according to either the validated AFNOR ALOA One Count method or the AFNOR NF V 45-008 method.

Results

48 samples of sliced smoked salmons were analyzed at day zero, see table below. Listeria monocytogenes was detected on 21% of the samples (10 out 48). The initial contamination level on these 10 samples was low (< 2 CFU/g).

Of the 10 samples that tested positive at day zero for Listeria monocytogenes, 6 control samples were negative on Day 28 and at 4 samples the Listeria counts were ranging from 100 to 1400 per gram. For the smoked salmon treated with phage, Listeria monocytogenes was not detected in any of the samples.

Conclusions

These results demonstrate that phage effectively controls Listeria on sliced smoked salmon naturally contaminated with L. monocytogenes and stored during 28 days at low temperature.

  • Listeria monocytogenes was detected at day zero on 10 out of 48 samples 21%

 

For 4 samples, the contamination levels at the end of shelf-life were ranging from 100 to 1400 Listeria monocytogenes per gram for the slice part not treated with phages (control) while for the slice part treated with phages, Listeria monocytogenes was not detected.

Source

Ofimer research report 2011. Use of phages to control Listeria monocytogenes in smoked salmon. Research partners CITPPM, Adria and Micreos Food Safety.

About Micreos & PhageGuardPhageGuard

Micreos is a pioneer in the field of targeted antibacterial technology. We develop cutting-edge proprietary products and technology, among which the PhageGuard product line. Our success is based on a history of successful collaborations with top universities, institutes and customers around the globe. Our innovative research is regularly featured in scientific journals and media publications worldwide.

For more information

Curious to find out how Phages can improve food safety at your facility, require more information, or simply interested in discussing Phage-use? Feel free to contact us using the information below.

sales@micreos.com or Contact us.

Share this news article
Posted : 2019 , News