The present invention relates to phage isolates having a strong lytic activity against pathogenic Enterobacteriaceae such as Escherichia coli and/or Salmonella strains and their use in various human or pet food products for the treatment or prevention of bacterial diseases caused by pathogenic Enterobacteriaceae such as Escherichia coli, in particular for phage therapy of pediatric gastroenteritis, or Salmonella infection. It also relates to human or pet food products prepared thereof.