Relationship between time-to-detection (TTD) and the biological parameters of Pichia anomala IG02; modelling of TTD as a function of temperature, NaCl concentration, and pH and quantification of their effects.
The time to detection (TTD) for Pichia anomala IG02 was defined, for inoculum sizes lower than 6 log(10)cfu/ml, as the time elapsed from inoculation to the moment at which an OD of 0.12 was reached. In other cases, TTD can be estimated by interpolation within the time elapsed from the previous readings below OD=0.12 and the next above it. A linear relationship, which depended on the inoculum size, between lnTTD with ln lambda and ln mu(m) was found. These relationships can be used to estimate the biological parameters of cultures with low inoculum levels. In addition, TTD for P. anomala IG02 could be modelled as a function of environmental conditions. The model can also be applied to lambda and mu(m) through their relationships with TTD. The effects of temperature, NaCl content and pH were quantified by the generalized z-values. An increase of 5.97 in NaCl concentration, a decrease of 1.97 units of pH, or a decrease of 6.08 degrees C doubled the TTD or caused a 2.53-fold increase in lambda and a 2.56-fold decrease in the mu(m).
Arroyo López
F N
FN
Departamento de Biotecnología de Alimentos, Instituto de la Grasa (CSIC), Apartado 1078, 41012 Sevilla, Spain.
Durán Quintana
M C
MC
Garrido Fernández
A
A
D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008954:Models, Biological; D031658:Olea / Q000382:microbiology; D010843:Pichia / Q000187:drug effects* / Q000254:growth & development*; D012965:Sodium Chloride / Q000494:pharmacology*; D013696:Temperature; D013997:Time Factors
D012965:Sodium Chloride