Final answer:
2) Food preservation techniques. Thermal processing and chilling are food preservation techniques that control microbial growth to extend shelf life and maintain food safety. Thermal processing uses heat to kill or deactivate microbes, while chilling slows or stops their growth without sterilizing the food.
Step-by-step explanation:
Thermal processing and chilling are examples of food preservation techniques. These methods have been important in extending the shelf life of food and maintaining its safety by controlling microbial growth. Thermal processing includes heating food to a specific temperature for a set period, which helps in altering the membranes of microbes and denaturing their proteins, thereby killing them or reducing their activity. The exact parameters like the thermal death point (TDP) and thermal death time (TDT) are important for determining the effectiveness of heat treatment for different microorganisms.
Chilling, on the other hand, involves the reduction of temperature to slow down microbial growth. Refrigeration merely slows down the growth, while freezing stops it entirely, sometimes resulting in the death of some organisms. While chilling doesn't sterilize food, it is effective enough to keep food safe for consumption over a short period.
These methods are integral to food safety and are preferred over methods like boiling and autoclaving for many foods since they maintain the food's quality, unlike sterilization that may alter the texture and taste of the product. Pasteurization, a form of thermal processing, is particularly famous for preserving milk by killing pathogens without affecting the nutritional quality, thanks to Louis Pasteur's developments in the 1860s