Relationship of season with milk characteristics, yield, and shelf life of cheese in a hot climate

Objective: the objective of the study was to identify whether there is a relationship between the environmental conditions of high temperature and humidity with the parameters of cheese yield and shelf life of Oaxacatype cheese, made throughout two different times of the year, delimited by environmental temperature, in the Mexicali Valley, Baja California, Mexico. Design/Methodology/Approach: from January to November, ambient temperature and relative humidity, characteristics of the milk used at the time of reception (temperature, acidity, density, somatic cell count and microorganism count), yield, and shelf life of the cheese were recorded. These variables were related to season (summer and winter) and to different Temperature and Humidity Index– THI intervals. An analysis of variance was performed, also, the relationship among sets of variables by Pearson correlation, and the multiple mean difference with the Tukey test (p0.05). Results: significant differences were observed in the density, acidity, temperature, somatic cell count and cheese yield of milk due to the effect of the time of year. In addition, an 11% decrease in cheese yield was found as the maximum THI exceeded 77 units. The shelf life showed positive significant difference (p0.05) when milk was pasteurized, but it was not affected by the THI. Limitations/Implications of the study: this study was limited to a single period of analysis; so, it is necessary to monitor, and include additional milk quality variables. Conclusions: heat environmental conditions negatively impact the characteristics of the milk, therefore reducing the yield of Oaxaca-type cheese. The microbiological characteristics are unfavorable during the hot season; the pasteurization of milk is the main factor that increases the shelf life of the cheese.