The use of phage or phage products in food production has recently become an option for the food industry as a novel method for biocontrol of unwanted pathogens, enhancing the safety of especially fresh and ready-to-eat food products. While it can be expected that many more phage products currently under development might become available in the future, several questions may be raised concerning the use of such products, regarding both immediate and long-term efficacy, consumer safety, and application methods. The available evidence suggests that, with a few caveats, safety concerns have been satisfactorily addressed. Answers concerning efficacy are more complex, depending on particular applications or the target pathogens. To ensure long-term efficacy beyond what can be tested on a laboratory scale, food safety concepts employing phages will have to be well-thought out and may involve rotation schemes as used with bacterial starter cultures, the use of phage cocktails, or application of phages combined with other antimicrobials. This review will discuss these issues on the basis of the available literature as well as providing an outlook on the potential of phages in future applications.

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SummaryWe report isolation and characterization of the novel T4-like Salmonella bacteriophage vB_SenM-S16. S16 features a T-even morphology and a highly modified 160 kbp dsDNA genome with 36.9 mol % G+C, containing 269 putative coding sequences and three tRNA genes. S16 is a virulent phage, and exhibits a maximally broad host range within the genus Salmonella, but does not infect other bacteria. Synthesis of functional S16 full-length long tail fibre (LTF) in Escherichia coli was possible by coexpression of gp37 and gp38. Surface plasmon resonance analysis revealed nanomolar equilibrium affinity of the LTF to its receptor on Salmonella cells. We show that OmpC serves as primary binding ligand, and that S16 adsorption can be transferred to E. coli by substitution of ompC with the Salmonella homologue. S16 also infects 'rough' Salmonella strains which are defective in lipopolysaccharide synthesis and/or its carbohydrate substitution, indicating that this interaction does not require an intact LPS structure. Altogether, its virulent nature, broad host range and apparent lack of host DNA transduction render S16 highly suitable for biocontrol of Salmonella in foods and animal production. The S16 LTF represents a highly specific affinity reagent useful for cell decoration and labelling, as well as bacterial immobilization and separation.