Activation of Probiotic Cultures Treated with Extremely low Fequency Magnetic Field

Abstract

The effect of the extremely low frequency oscillate magnetic field (LEF-OMF) was evaluated on the viability of three probiotics cultures for yogurt: Lactobacillus acidophilus, Lactobacillus casei and Bioyogurt. The cultures inoculated in 50 mL of 9 % not fatty milk were treated CMO-FEB of 60 Hz and density from 1 to 20 Gauss (G) during 10 to 60 min, according to of D-optimum experiment design. Response variables were the viability (Log ufc/mL) and the morphology of each microorganism. The applied treatment had bigger stimulated effect on L. acidophilus and L. casei (increasing 1,8 and 1,4 log ufc/mL, respectively) while the viability of the cultivation of Bioyogurt after treated (1,3 to 8,2 log ufc/mL) never overcame to the value control (9,5 log ufc/mL). The viability of the L. acidophilus (10,71 log ufc/mL) was bigger than L. casei (8,97 Log ufc/mL) and decreasing of this variable (window) between 9 and 11 G for both cultures was observed. In this range a thickness of the lactobacillus cellular wall was observed that didn't affect its bacillary form and with 20 G bacilli were deformed while the cocci of Bioyogurt culture conserved typical morphology in all time. The numeric optimization of design indicated 35 min and 10 G like the appropriate regime to reach the maximum viability. Was conclude the applied CMO-FEB has bigger effect on the bacillary morphology and stimulates more the viability of the lactobacillus like pure culture that cocci when they form a mixed culture.