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Applicability of commercial phage-based products against Listeria monocytogenes for improvement of food safety in Spanish dry-cured ham and food contact surfaces.
Food Control, 2017
Gutiérrez, D., Rodríguez-Rubio, L., Fernández, L., Martínez, B., Rodríguez, A., and García, P.
The efficacy of bacteriophages as antimicrobials has fostered the approval and commercialization of several products intended to reduce the risk of food contamination by pathogenic bacteria. ListShield™ and Listex™ P100 are bacteriophage preparations that aim to combat Listeria monocytogenes in food industries. Here, we assessed the effectiveness of these phage-based products against L. monocytogenes strains from food origin. Both, removal of L. monocytogenes biofilms and inhibition of growth in Spanish dry-cured ham were evaluated for this bacterium. ListShield™ was effective in lysing 100% of L. monocytogenes strains examined, whereas Listex™ P100 lysed only 64% of the same strains. According to the manufacturers' recommendations, ListShield™ was used in a lower concentration than Listex™ P100 for the efficacy studies. Despite these differences, both products were effective in removing 72 h-old biofilms formed on stainless steel surfaces by most of the assayed strains after a 4 h treatment at 12°C. For some strains, moreover, complete removal of adhered bacteria from 48 h-old biofilms formed on polystyrene surfaces was obtained after 4 h of treatment at 32°C with Listex™ P100. Evaluation of phage-based products as bio-preservatives in dry-cured ham showed that the application of Listex™ P100 resulted in a reduction of L. monocytogenes contamination below the detection limit (<10 CFU/cm2) after 24 h at 4°C and 12°C. Treatment with ListShield™ showed similar results with the exception of samples with a high level of contamination (105 CFU/cm2), in which a reduction of 3.5 log units was achieved after 14 days of incubation at 4°C. In contrast, the antibacterial activity of ListShield™ decreased in samples stored at 12°C, although a complete elimination of bacteria was observed after 8 days of treatment in low contaminated samples (103 CFU/cm2). All these results suggest that phage-based products can be useful for biocontrol of L. monocytogenes in food contact surfaces and dry-cured ham.
Listeria monocytogenes
Food Group
Food Product
Spanish style dry-cured ham
Spanish style dry-cured ham