There are several methods to detect the salt in food:

1. Silver chloride titration: This method is a common method to determine the salt content in food. The principle is to use silver chloride to react with chloride ions to generate precipitation, and determine the salt content in food by titration. The specific operation steps include taking a certain amount of food samples, adding an appropriate amount of water to dissolve them, adding silver chloride reagent to react with chloride ions in the samples to generate precipitates, titrating the silver chloride reagent until the precipitates disappear and recording the dropping amount, and finally calculating the salt content in the samples according to the dropping amount.

2. Conductivity method: Conductivity method is a method to determine the salt content in food by using conductivity. The principle is that the higher the salt content, the higher the electrical conductivity in food. The specific operation steps include taking a certain amount of food samples, adding an appropriate amount of water to dissolve them, inserting a conductivity meter into the samples to record the conductivity, and finally calculating the salt content in the samples according to the conductivity.

3. food salinity meter: this is a device that can measure the salt content in food, not only the temperature of food, but also a dual-purpose machine. It can be used to detect the salinity of stews, marinades, sauces, salt water, etc. in home cooking, and can also be used to control the products in restaurants, thus reducing the cost of rework. Generally speaking, the salinity of stew is controlled at .8%~1.2%, and the salinity of brine is controlled at 1.2%~1.6%. In addition, it can also be used in aquaculture, pharmaceutical preparation, industrial production and other fields. This kind of equipment usually has the function of quick response, large-screen numerical display, and can easily judge the salt content.

All the above methods can detect the salt in food, and which method to choose mainly depends on the specific situation and needs. If accurate measurement results are needed, it is recommended to use professional laboratory equipment.