title: Semi-automated direct epifluorescent filter technique for total bacterial count in raw milk.
abstract: The Direct Epifluorescent Filter Technique (DEFT) and the reference method of counting total bacterial colonies on Petri dishes were compared. IDF Standards 128 (1985) and 161A (1995) were applied. A total of 496 samples of milk were analyzed. Colony forming units per microL milk were transformed to decimal logarithmic units: log (cfu/microL). The repeatability standard deviation, Sr = 0.114, was typical for a routine microbiological method. To study the carryover at different levels of bacteria, 3 tests were performed on milk samples of approximately 100, 700, and >1000 cfu/microL. For the first 2 experiments, no carryover was detected; in the milk sample with >1000 cfu/microL, the carryover was <0.12%. When the DEFT counts were regressed versus the reference method, the values of the slope and intercept were 0.92 and 0.17, respectively; the correlation coefficient was r = 0.84; and the residual standard deviation was Syx = 0.287. The paired t-test showed that the reference method and DEFT do not give significantly different results (p = 0.05).
authors: Laboratorio de Mouriscade, Deputación Provincial de Pontevedra, Spain.
authors: M
authors: M
authors: Hermida
authors: M
authors: M
authors: Taboada
authors: S
authors: S
authors: Menéndez
authors: J L
authors: JL
authors: Rodríguez-Otero
mesh_terms: D000818:Animals; D002138:Calibration; D002417:Cattle; D015169:Colony Count, Microbial / Q000379:methods*; D005374:Filtration; D007202:Indicators and Reagents; D008892:Milk / Q000382:microbiology*; D012015:Reference Standards; D015203:Reproducibility of Results; D012996:Solutions; D013050:Spectrometry, Fluorescence
chemical_list: D007202:Indicators and Reagents; D012996:Solutions