Authors:Pinar Şanlibaba, S. Buzrul, Nefİse Akkoç, H. Alpas, and M. Akçlİk
Survival curves of
bacteriophage pll98 inactivated by heat were obtained at seven temperature values (50–80°C) in M17 broth and skim milk. Deviations from first-order kinetics in both media were observed as sigmoidal shapes in the survival curves of pll98. An empirical model with four parameters was used to define the thermal inactivation. Number of parameters of the model was reduced from four to two in order to increase the robustness of the model. The reduced model produced comparable fits to the full model. Both the survival data and the calculations done using the reduced model (time necessary to reduce the number of phage pll98 six- or seven- log10) indicated that skim milk is a more protective medium than M17 broth within the assayed temperature range.
Authors:Ça?la Tükel, Pinar Şanlibaba, Banu Özden, M. Akçelik, and M. Akçelik
98 Lactococcus lactis strains were isolated from traditional fermented milk products in Turkey tested against 60 lactococcal lytic phages to determine their resistance levels. While 82 L. lactis strains were sensitive against lactic phages at different levels, 16 L. lactis strains showed resistance to all phages tested. Types of phage resistance among 16 L. lactis strains were identified as phage adsorption inhibition in eight strains, restriction/modification in six strains and abortive infection (heat sensitive phage resistance) in two strains, using three broad-spectrum phages Fpll 98-32, Fpld 67-42 and Fpld 67-44.