The reason why crackers don't go bad is because crackers are low in moisture content, which is what prevents the crackers from growing mold and bacteria.
And commercially made crackers are also made with preservatives and are also packed in airtight containers that have an inert gas that prevents oxidation, which keeps them from fresh for months.
However crackers can go bad in becoming stale, and the stale crackers are a result of the crackers absorbing moisture from the air and not from any harmful breakdown of the crackers themselves.
Once the package is opened, crackers can go bad as the crackers are exposed to air and moisture.
And when the crackers absorb the moisture, the crackers become soft and stale, which can eventually allow the crackers to grow mold and bacteria.
The fats in the crackers can also become rancid over time, which can also result in an unpleasant smell and taste, although it's different from the texture change of the crackers becoming stale.
The crackers that have the longest shelf life are Keebler crackers, Keebler pretzel "flipsides", pilot bread and hardtack crackers.
Pilot bread crackers and hardtack crackers are designed specifically for long term storage and when stored properly they can last 30 years or longer when they are kept sealed in a can with an oxygen absorber.
Other crackers that are packed in individual airtight packages will last longer than the standard boxed crackers, but they will also not be as long lasting as canned pilot bread.
Pilot bread and hardtack crackers are very dense crackers that are made from some basic ingredients such as water, flour and salt.
And they are usually sold in cans that have an oxygen absorber to prevent rancidity and extend the shelf life for up to 30 years.
Bacteria can grow on crackers, especially when the crackers are moist or stored in damp or humid locations.
And the bacteria which is harmful bacteria can not only grow on crackers, but the harmful bacteria on the crackers can also survive and thrive on the crackers for months.
Although on dry crackers are unlikely to grow any bacteria as bacteria require moisture to grow.
However pathogens like Salmonella can survive in dry and low water activity foods like cookies and crackers.
Crackers are considered to be a low risk food, because crackers have low water activity, which prevents bacteria from multiplying.
And although bacteria can't grow in the dry environment of the crackers and cookies, the bacteria can however survive in dormant states for a long time in dry foods.
Bacterial contamination of the crackers and cookies can also happen during the manufacturing process, like through contaminated ingredients such as flavored whey powder or other ingredients.
In cracker sandwiches, for example, the filling is what is more likely to support the growth of bacteria and survival of bacteria instead of the cracker itself.
To prevent bacterial growth and bacterial survival of your crackers, you should store the crackers in a dry environment and keep them away rom moisture.
Most often crackers will go rancid or stale before they grow any mold.
If the crackers smell bad or rancid or smell strongly of vinegar then throw them out.
Crackers can smell of vinegar as a result of rancid oils in the crackers or if they are sourdough crackers, from hungry starter.
The vinegar smell from rancid oils and rancid crackers indicates spoilage and it can also indicate a quality issue which might make the crackers unappealing to eat.
Although the bad taste will likely prevent you from eating them.