re boiling stock
Your asking whether or not it is legal is not the same as asking if it is safe or asking if it retains quality. There are many factors in play here.
As with expiration dates and sell by dates, the legal status does not equate with quality retention.
Is the stock gelatinous? High gelatin content will inhibit or prevent bacteria from spoiling the whole batch because the bacteria will not be able to permeate throughout the stock. This does not mean it won't spoil, it just stays good longer.
After six days, is the stock sour or taste off before or after reboiling? If it is the same in taste and appearance, there is nothing wrong with it. If it has not spoiled, why dispose of it?
The same foods may spoil quickly or they may enjoy a long shelf life depending on many factors. Determining what has retained it's usability requires experience and good judgement. Not all employees can be expected to have either so the legal limits are in place to insure some measure of protection for the public good by removing debate and providing some guidelines.
For the general public, these legal limits are guidelines typically in the form of expiration and sell by dates. If you buy milk the day before the expiration date, but don't drink it all at once, in two days it will have "expired" legally. The milk does not automatically spoil at midnight on that date. When it does spoil, you will know it no matter what the date on the carton may say.
Large foodservice companies such as Aramark and Sodexo often have in-house guidelines for what, when and how various prepared foods should be disposed of. As they service large groups of people at one meal time, the affects of any spoilage are going to impact many all at once. They can not rely on every employee having the experience and good judgement to heat and cool foods correctly every time or to understand when spoilage or unsafe conditions have rendered the food potentially unsafe in a given situation. So they institute their own guidelines to insure safety for their clients. As a result, a lot of food is disposed of long before it is spoiled.
The Health Department and Serv Safe programs do much the same thing. `They cannot be on site at every restaurant or be present for every meal. The regulations for food quality are based on science and a developed understanding of what happens at different temperatures over time. It is commonly understood that bacteria grow best between 40 and 140 degrees. If left in this range for a certain length of time, the chances of spoilage increase dramatically. Not in every case, every time for every food product under any circumstance, but generally.
Proper storage of ingredients within the storage areas also plays a role. That is why the Health Departments require raw chicken to be stored in the refrigerator on the bottom shelf. Fresh soup or sauce dripping into a box of raw chicken is not good, but not as dangerous as raw chicken dripping into a fresh soup or sauce.
Sooo… a stock (or any other food) properly prepared and properly stored may retain it's edibility for quite some time. Or it may spoil in a very short period of time. Throwing food away after a predetermined time frame may be efficient from a safety standpoint but if the food has not spoiled it is also wasteful. All things being equal (general sanitation, good practices, etc), your chef is using his experience and judgement to maintain quality while saving the business money. Without any more information on your particular situation, I'll support the chef's decision.
+1. I agree with chefwriter, you have to be reasonable with this things. If it is nothing wrong with it would be crazy to throw it away. Boiling it will extend it's life, I do the same then try and if tastes OK, looks Ok I keep it. If it hasn't gone sour or is not foaming when re-boiled it is OK. I don't agree with using it another 7 days as a rule that is just stupid Sometimes same product goes off quicker than other times. You have to be safe but not wasteful as well. If you keep to the proper storing, cooling down, refrigerating procedures you can keep your stuff safe. For example I keep my steaks in oil marinating with herbs and garlic, they taste better, and last longer. Any steak I don't sell within 3 days of purchase I should throw away according to Health and Safety people, but do I do it? #@!?ck no! Use your head and experience. I have one rule though if you not sure throw it away!
Where I work now we have a 3 day rule on most mise with a few exceptions. After 3 days it becomes staff meal. The food is obviously still safe but the quality may start to deteriorate. It's a good rule because it is an exact cut off date and eliminates the possibility for hacks to try and use questionable products. It can also help with pars and prep because you know when you'll have to make the next batch and can make a prep schedule for the whole week. Although it hurts when you prepped a lot of something 2 days ago and have to remake it when you still have plenty. But it does make sure the guest is always getting good food.