Dataset on the use of the Ratkowsky model for describing the influence of storage temperature on microbial growth in hake fillets (Merluccius merluccius) stored under MAP

This article presents the results obtained after applying the Ratkowsky model for developing secondary models describing the influence of storage temperature on microbial growth in hake fillets packaged under a modified atmosphere (MAP) rich in CO2 (50% CO2/50% N2). For this purpose the growth parameters (λ, μmax) already calculated in the related article “Modelling microbial growth in Modified-Atmosphere-Packed hake (Merluccius merluccius) fillets stored at different temperatures” [1] were used. The data include the fit and goodness of the fit parameters calculated as well as the comparison between fitted and observed data.


Data
Growth curves in hake fillets stored under MAP (50% CO 2 /50% N 2 ) of 8 microbial groups were obtained and fitted using the Baranyi and Roberts model [2,3] in the related research article "Modelling microbial growth in Modified-Atmosphere-Packed hake (Merluccius merluccius) fillets stored at different temperatures" (Table 1). In this article the Ratkowsky and inverse Ratkowsky model [4,5] are used for describing the influence of storage temperature on the previously calculated growth parameters (m max and l). The influence of storage temperature on the mmax (2) and l (3) values calculated for each bacterial group (non-specific: 1A and 2A; specific: 1B and 2B) is shown in Figs. 1 and 2 and the values calculated for the fit parameters (b, T min ) together with its standard errors are included in Table 2 (storage temperature vsm max ) and Table 3 (storage temperature vs l). The secondary models developed are included in Table 4. Experimentally determined values were compared with those predicted by the models and these results are shown in Fig. 3, which includes data from all the storage temperatures assayed. It also includes the R 2 and RMSE values calculated for each microbial group.

Value of the Data
The data here presented can be used for estimating the shelf-life of hake stored under MAP at different temperatures. These data might be useful not only for the fishery industry, but also for food safety authorities, retailers and even consumers. They can also be used to get further insights into the spoilage process of hake and to better understand the effect of temperature on hake's microbiota.
In contrast to the secondary models described in the related article "Modelling microbial growth in Modified-Atmosphere-Packed hake (Merluccius merluccius) fillets stored at different temperatures" those developed and included in this one are based on the widely used Ratkowsky model. This makes them easier to be implemented in already existing food safety and spoilage prediction programs and/or databases.     Table 4 Secondary models developed using for the different microbial groups in hake fillets stored under MAP (50% CO 2 /50% N 2 ) at different temperatures (T). The models are valid in the range between 1 and 10 C unless specifically stated.
The Ratkowsky model [4] was used for describing the influence of storage temperature on the m max . This model is defined by the following equation: Where ffiffiffiffiffiffiffiffiffiffi m max p is the square root of maximum growth rate, b is the slope of the regression line, T is temperature, and T 0 is a conceptual minimum temperature for microbial growth, where T and T 0 are given in C.
Three influence of storage temperature on lag time (l) was described with the inverse Ratkowsky model [5]: Where l is the lag time, b is the slope of the regression line, T is the temperature, and T 0 is a conceptual minimum temperature for microbial growth, where T and T 0 are given in C. GraphPad PRISM software (Graph Software, San Diego, CA) was used for curve fitting, and Microsoft Excel software (Microsoft, Seattle, WA) was used to calculate the goodness of the fit parameters (R 2 , RMSE).