Food spoilage is often caused by mold and other spoilage microorganisms. This case study focuses on determining how the medium properties as well as environmental conditions are correlated to microorganisms activity that can affect food safety and quality. In a series of experiments, a range of temperature conditions, substrate pH values and water activity were varied using the values presented in Table 1. The resulting values of microorganisms activity were measured (see in Table 2) with the aim of finding those conditions that help us preserving foods longer. Table 2. Microorganism activity (U/mL) resulting from the experiments performed. Using the given data set: (iv) what is the response surface model that better fits the data? Consider initially a full quadratic model. Discuss the significance of the terms and possible model simplifications. (28 marks) (iii) analyse and discuss the effect of factors and their interactions on the response variable. Use suitable graphs to present and present your results ( 18 marks) (v) predict the model response for Temperature =38C,Ph=7, Water activity =0.4%w/v with 99% confidence ( 8 marks) (vi) what is the minimum microorganisms activity achievable and what are the operating conditions that lead to that value? (12 marks)