This document discusses intrinsic factors that affect microbial growth in foods, including nutrient content, pH, redox potential, water activity, and antimicrobial barriers. It explains that microbes require nutrients like water, energy sources, nitrogen, vitamins and minerals. The pH and water activity of foods can determine which microbes can grow. Redox potential influences whether microbes are aerobic or anaerobic. Certain food constituents like essential oils and lysozyme in eggs have natural antimicrobial properties. Overall, the document provides an overview of how the inherent properties of foods can promote or inhibit microbial growth.