One point emerge that is storage time and bacterial count is related.Now u can check the same through correlation followed by regression for curve fitting.

Another way arrange your data for one-way anova(three observations under each storage time)and run analysis in SPSS to check if there is any difference in mean count..

For each storage period, you may have many plates and bacterial count for each plate. Thus, you will have three groups of data: the 0 storage period group, the 3, and the 6 storage period group. You can compare the means counts of each group by using the One-Way ANOVA ("analysis of variance"). You can also get the comparison results of any two groups through ANOVA ( Post Hoc analysis).

Please refer to the following link which clear show how to run ANOVA in SPSS:

https://libguides.library.kent.edu/SPSS/OneWayANOVA

Jamal,

You can do One way ANOVA test for your results based on deferent months. According to your test,

H0- There is no deference between the storage time and bacterial count

H1 -There is a deference between the storage time and bacterial count

You can process SPSS or MINITAB software to analyze the test and if your p value similar or lessthan 0.05 that means your null hypothesis rejected and H1 accepted.

there is more than one method possibly available, the choice between these depends heavily on the data - send some