Summary
Abstract
The presence of Listeria monocytogenes in food processing environment is a risk of food contamination by persistent cells due to their ability to attach to stainless steel and other surfaces. We aimed to study biofilms formation of lux-tagged L. monocytogenes EGDe on stainless steel surfaces and their control using neutral electrolyzed water (NEW), where biofilms development was monitored using destructive and non-destructive microscopy techniques. The development of biofilms was monitored for 5 days on stainless steel chips. We used two sources of NEW, commercial (NEW-1) and from a prototype (NEW-2) for treatments of free and biofilm L. monocytogenes EGDe cells. Complete inhibition of L. monocytogenes EGDe free cells was observed after 1 min contact time for both NEW sources, but NEW-1 concentration used (9 mg/L total available chlorine, TAC) was 1.8 times higher. Cells within biofilms were more resistant to NEW compared to planktonic cells. Same concentration of both NEW sources (70 mg/L TAC) exhibited complete inhibition of biofilm cells after 3 min contact time. However, using a sub-lethal dose of 40 mg/L TAC, NEW-2 reduced about 2 log CFU/cm2 biofilm cells while NEW-1 inhibited 0.3 log CFU/cm2 only. Biofilms formation and antagonistic effect of NEW could be visualized by epifluorescence and scanning electron microscopy, revealing significant biofilms structure. The disinfectant effect of NEW may be attributed to the combined antimicrobial effect of available chlorine and high ORP exhibited by its oxidizing compounds. NEW does not promote metal equipment corrosion due to its neutral pH, and is also environmentally friendly.
Study details
- Published in: Food Control 34.2 (2013): 472-477
- Microbes studied: Listeria monocytogenes
Source
Source: Food Control 34.2 (2013): 472-477
Conditions tested
| Parameter | Value |
|---|---|
| Organisms | Listeria monocytogenes |
| Relevant sectors | Food Processing, Food safety |
| Publication | Food Control, 2013 |
Reading this responsibly
Published figures are obtained under controlled conditions, usually on clean surfaces or in defined matrices. Organic load, surface condition, temperature and application coverage all affect real-world performance. Use these numbers to design a protocol, then validate it on your own site with environmental swabbing.
Applying it
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