Isolation and characterization of a Lactobacillus plantarum bacteriophage isolated from a meat starter culture*

Morphological characterization of a bacteriophage isolated from the Lactobacillus plantarum portion of a commercial meat starter culture showed that the isolate, phage fri, belonged to the Bradley group A bacteriophages. It had a regular six‐sided head (90 nm diameter), and a contractile tail (190 nm in length). Short tail fibres were observed at the distal end of the sheath. Fluorescent staining with acridine orange indicated that phage fri contained double‐stranded DNA. The resistance to high concentrations of either chloroform or ether showed that its lipid content was negligible. Heat lability was demonstrated by inactivation of a phage fri population within 10 min at 60°C and within 5 min at 70°C. It tolerated pH levels of 3.0–8.0 and exhibited greater stability in the acid region than did its host strain. The latent and rise periods were both 75 min, and the average burst size 200 pfu/cell. Sensitivity was limited to the Lact. plantarum strain of only one manufacturer of the commercial meat starters investigated.