How can I know that the food is bad in a min without any lab analysis?

If expired the Validity , the presence of mold, bulging cans, when you change the smell and taste, bad storage conditions, the presence of insects or foreign matter where, and no cases of poisoning from the same food ....

You're gonna have to resort to your senses.  That's the basic test humans have always used to determine if their food is fit for consumption.  That includes the detection of undesirable odours, unusual texture, or any other sensory abnormalities.  And that's where the dilemma of expiry/best before date strikes in.

Just check four things taste , odour , color and texture 

It will give you a basic knowledge of what you are facing 

Because I did enginnering degree on Food Technology, I think fisrt of all after you buy your food, you need to check the ingredients, so if you find like E211, Acid Citric etc... There is a long list for all indesirable chemical addetifs.

But if you buy any other food like fresh one so you'll be able to see if it is good damage or not, and if you buy like juices or meat this have an other way, firt the first image you're seeing, like drinks if you see is like water with color chemical of course you wont buy them, example Sport juices, Red Bull, Coca Cola, Pepsi, all of these are just a slowly way to destry your body with time.

For the meat, so use your smell and eyes, smeel if it is indesirable one, and eyes to distinct the color, if it is over Red means is not a good one, So you've a los of cretarias to distinct a good food from the bad one. Concerning me I spend more then an hour to do my shooping cause it is about my health.

Thank you

Of course. The sense of our own organs (Eye, Ear,Nose and Tongue)  can determine WHETHER THE FOOD IS EDIBLE TO TAKE OR NOT.

Then your knowledge about the foods available around the world,

• it is the "best use by date"which shows the shelf life of the product and generally all the food product have their shelf life by which we can determine the acceptabilty of the product like bread shuold be used within max 7 days of manufacturing 
• External factors like appearance  (size, shape, colour, gloss, and consistency), texture, and flavour.
• Internal  factors (chemical, physical, microbial).

bad smell and expiry date

some fungus formed in the food

 change of  Color ,odor ;texture

by organoleptic analysis  and knowledge about the particular ingredient used in the food