anaerobic bacteria analysis of food Analysis of milk animal virus bacteria bacteria identification bacteria isolation bacteriophage Cultivation differentiation staining Dissolved Oxygen Of Water DNA DNA replication DNA sequence enzyme exotoxin Food microbiology gene genetics gram positive Grams staining immune reactions immune system Immunology infection Isolation of microorganism mendel microbiology milk MR test mutant mutation Plasmid staining Staphylococcus Sterilization streptococcus toxin transduction transformation virology virus virus properties water water quality