ABSTRACT
Bacterial growth in food occurs though the metabolism of food components or nutrients mainly in the cytoplasm and cytoplasmic membrane (also in periplasmic space in Gram-negative bacteria) of cells. 1 The complete process involves the transport of nutrients from the environment (for macromolecules after their enzymatic breakdown) inside the cell through the cell wall and cell membrane, the breakdown of nutrients to generate energy and active building blocks, the synthesis of cell components from the building blocks (mainly macromolecules and structural and functional components), and the release of unusable end products into the environment. In addition, the recycling of cellular materials, cell differentiation, the repair of injured structures, and adaptation to environmental stresses are also mediated through metabolic processes. Some of these aspects are important in food microbiology and are briefly discussed in several sections in this book: sporulation in Chapter 9, sublethal injury and repair and stress adaptation in Chapter 10, and nutrient transport in Chapter 12. Several energy-generation and energy-degradation processes that are important in food microbiology are briefly discussed here (and also in Chapter 12).
