Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli studi di Milano, Milan, Italy.
J Appl Microbiol. 2022 Jan;132(1):642-653. doi: 10.1111/jam.15215. Epub 2021 Jul 26.
The two-parameter (α and β) Schiraldi's model reliably fits growth curves of psychrotrophic pathogens and suggests a different description of the latency phase.
Data obtained at various temperatures and different starting cell densities for Aeromonas hydrophila, Listeria monocytogenes and Yersinia enterocolitica have been fitted with the Baranyi and Roberts' model and the new one. On average, the former showed higher standard error and R values (0.140 and 0.991) than the Schiraldi's one (0.079 and 0.983). Around 15℃, the increase of temperature showed a milder effect on the growth rate than that expected. Y. enterocolitica showed a practically null duration of the lag phase, no matter the value of the starting density, whereas A. hydrophila and L. monocytogenes revealed slower onset trends.
Parameter β defines the number of cell duplications and appears independent on temperature, while (β/α) is proportional to the maximum specific growth rate. The α versus temperature trend directly reflects the corresponding behaviour of the growth rate and does not require the use of Arrhenius plots.
Values of the parameters α and β, as well as the duration of the latency phase, allowed some considerations about the effect of storage temperature in terms of food safety, especially for psychrotrophic bacteria of concern.
双参数（α和β）Schiraldi 模型可靠地拟合了低温嗜热病原体的生长曲线，并对潜伏期提出了不同的描述。
在不同温度和不同起始细胞密度下，对气单胞菌、单核细胞增生李斯特菌和小肠结肠炎耶尔森菌的数据进行了 Baranyi 和 Roberts 模型及新模型的拟合。平均而言，前者的标准误差和 R 值（0.140 和 0.991）高于 Schiraldi 模型（0.079 和 0.983）。在 15℃左右，温度升高对生长速率的影响比预期的要温和。无论起始密度如何，小肠结肠炎耶尔森菌的潜伏期实际上为零，而气单胞菌和单核细胞增生李斯特菌的潜伏期则呈现出较慢的起始趋势。
参数β定义了细胞倍增的数量，并且似乎与温度无关，而（β/α）与最大比生长速率成正比。α与温度的趋势直接反映了生长速率的相应行为，不需要使用阿累尼乌斯图。
参数α和β的值以及潜伏期的持续时间，使我们能够从食品安全的角度考虑储存温度的影响，特别是对于需要关注的低温嗜热细菌。
