* Reduced Water Content: Drying removes most of the water, which is essential for bacteria and other microorganisms to thrive. Without water, their metabolic processes slow down significantly.
* Increased Salt Content: Many drying methods involve salting, which further inhibits microbial growth. Salt dehydrates cells and makes it difficult for bacteria to multiply.
* Low Moisture Activity: Dried fish has a very low water activity (aw), which is a measure of the water available for microbial growth. Bacteria need a certain aw level to survive.
* Preservation Techniques: Traditional methods of drying, like sun-drying or smoking, often involve additional steps that kill bacteria and microorganisms.
However, it's important to note that:
* Conditions Matter: Even dried fish can spoil if exposed to high humidity, improper storage, or contamination.
* Spoilage Happens: While the process is slower, dried fish can still be affected by certain types of bacteria, molds, and insects.
So, while drying significantly extends the shelf life of fish and makes it less susceptible to decay, it's not completely impervious to spoilage.