FREEZE-DRIED SPINACH POWDER INHIBITS GROWTH OF LISTERIA SPECIES AND STRAINS IN TRYPTIC SOY BROTH

a study was undertaken to determine the inhibitory effect of freeze-dr ied spinach (Spinacia oleracea L.) powder and its native mesophilic ae robic microorganisms (MAM) on the growth of sis strains, representing three species, of Listeria in tryptic soy broth (TSB), The cultures we re incubated at 10 degrees C and growth was measured daily. Both spina ch powder and MAM inhibited growth; maximum populations at 6 days were 8.8 Log(10) colony-forming units (cfu) per mL(-1) in control, 6.4 in spinach powder cultures, and 7.4 in MAM cultures, These results indica ted that growth of various Listeria species/strains was affected by th e bacteriostatic effect of spinach powder and competitive effect of na tive microorganisms.