Phage applications for improving food safety and infection control in Egypt

Abstract

Aims: The study investigated the use of bacteriophages to control bacterial contamination of chicken skin, eggs, tomatoes and meat.

Methods and results: Experiments were performed to test the host ranges and killing potential of two isolated phages, ZCSE1 and ZCEC1, with hosts Salmonella and Escherichia coli respectively. The efficacy of both phages was determined by comparing the viable counts of recovered bacteria from treatment and phage-free control samples. In vitro experiments showed that phage ZCSE1 was able to reduce the numbers of Salmonella enterica ATCC 25566 to below 4·0 log₁₀ CFU per ml (3·4 log₁₀ CFU per ml reduction) in 240 min postinfection and phage ZCEC1 reduced the number of E. coli ATCC 8739 to undetectable levels (6·45 log₁₀ CFU per ml reduction) during the first hour of infection at 37°C. When applied to chicken skin and the surface of eggs, phage ZCSE1 treatment reduced the number of S. enterica ATCC 25566 by 2 log₁₀ and to undetectable levels (<2·0 log₁₀ CFU per ml), for skin and eggs respectively (P < 0·005). The administration of ZCEC1 phage to meat and tomatoes reduced the number of E. coli to below 2·0 log₁₀ CFU per ml 1 day after treatment.

Conclusions: The administration of these phages to meat and tomatoes reduced the numbers of E. coli and Salmonella significantly in tested foods.

Significance and impact of the study: The results suggest that phages could be effective treatments for pathogenic bacteria in food relevant contexts in Egypt.

Keywords: E. coli; Salmonella; food safety; infection control; phage.