Yin Shixiong explained to her that it didn't mean that she had to always keep an eye on how the kitchen was making food.
It meant that when possible, she should sneak in there before the food was ready to check how it was made, who made it, where the vegetables were bought, where the rice came from and where all the salt, sauces, and seasonings were produced.
The last and most important thing was to be the last one to eat or even eat the leftovers in someone else's bowl to avoid being the first to eat when having food in an unfamiliar place and when she had no way of checking how it was made if she couldn't cook it herself.
These were all lessons paid for using blood and sacrificed lives. People typically didn't have all those worries, but for someone in a special line of work, it was of the utmost importance.
