Detection of virulence genes in Pseudomonas fluorescens isolates from local cheese in Nineveh province

Cheese is a product highly consumed in Nineveh province, it is easily spoiled with pseudomonas fluorescens through preparation and processing, and the growth of these bacterium causes alteration in cheese quality, consequently reducing their shelf-life periods. Fifty samples of local cheeses sold in Nineveh province were screened to detect the existence of P. fluorescens as a food spoiler from October 2023 till March 2024.The P. fluorescens isolates from positive samples were tested to evaluate their virulence in producing exoenzymes causing cheese spoilage including, protease and lipase, by genetic approach of target genes using polymerase chain reaction assay. Out of 50 samples, 10(%20) were positive for the presence of P. fluorescens according to the 16SPflu gene. The activity of protease and lipase producing enzymes to positive isolates was detected depending on the AprX gene and LipM genes; the results revealed that 3(%30) of strains positive for AprX gene presence and 1(%10) of P. fluorescens strains possess the LipM gene indicated low lipase activity. Results of DNA partial sequencing of the 16SPflu gene revealed four strains recorded in the GenBank nucleotide sequence database with accession numbers PP727372, PP727373, PP727374, and PP727375. Our results shed light on the risk of P. fluorescens existence as a spoilage indicator in local cheese and confirm following the hygienic and sanitation conditions during cheese processing from milk and ensure the safety of raw milk during milk collecting, processing and preservation of cheese under chilling environments to prolong the shelf life of the products and ensure consumer health.