Primary and secondary modeling of Brochothrix thermosphacta growth under different temperature and ph values

Abstract Bochothrix thermosphacta is an optional aerobic psychrotrophic related to the meat deterioration and consequently loss of a refrigerated cargo contaminated. Predictive microbiology can be used as a quality assurance tool, since it allows the prediction of microbial response based in pass observations. This work aimed model the growth of B. thermosphacta under variation of pH and temperature. For this purpose, the experimental growth data were fitted to the primary models of Baranyi and Roberts and the modified Gompertz model and the data for the maximum rate of growth (μmax) were adjusted to Ratkowsky extended secondary model. The results showed us that the influence of temperature on growth parameters was more evident than pH. Since, by fixing the temperature the change of pH little altered the μmax. However, as the temperature rises the elevation at the μmax is considerable, for example the comparison of predicted values for μmax, when the temperature exceeds 4 °C to 12 °C, it is clear that these rates are more than double. Finally, it is emphasized that all tested models feature good fit to the experimental data, which makes them validated for prediction growth of B. thermosphacta in the same conditions tested experimentally.

摘要：热杀索丝菌（Bochothrix thermosphacta）是一类兼性需氧嗜冷菌，与肉类变质相关，可导致受污染冷藏货物的品质损失。预测微生物学可作为质量保障工具，因其可基于过往观测数据预测微生物的生长响应。本研究旨在构建pH与温度变化条件下热杀索丝菌的生长模型。为此，本研究将实验获得的生长数据分别拟合至Baranyi-Roberts一级模型与修正Gompertz模型，并将最大生长速率（μmax）数据拟合至Ratkowsky扩展二级模型。结果表明，相较于pH值，温度对生长参数的影响更为显著：在固定温度的条件下，pH值的变化对μmax的影响极小。但随着温度升高，μmax的增幅十分显著；例如，当温度从4℃升至12℃时，对比μmax的预测值可明显发现，此时的生长速率提升了一倍以上。最后，本研究强调，所有受试模型均能较好地拟合实验数据，表明这些模型可用于在本研究实验测试的相同条件下预测热杀索丝菌的生长情况。