The only definitive way to determine the presence of Listeria would be to submit a sample for lab analysis. It has a small infective dose and you cannot see it without microscopy.
No. Food can be contaminated with a variety of adulterants - most of which show no signs at all that they are present.
there are no warning signs
Green signs are not warning signs. They are signs that tell you it is "safe" to do something.
Food contaminated by dangerous bacteria like E. coli or Salmonella may exhibit signs such as an off odor, unusual color, or slimy texture. However, it's important to note that contaminated food can often appear normal and still be unsafe to eat. Cooking food thoroughly and following safe food handling practices are essential to prevent foodborne illness. Always check expiration dates and be cautious with any food that seems suspicious.
The most common color of warning signs is yellow.
After you eat the contaminated food
It depends on what warning signs that you are interested in. Many sites offer guides on how to spot the warning signs for illnesses etc. If it is to do with motoring check the highway site for details.
Early warning signs of storms and precautions
Cloths don't fit, always buying food, always eating food, frequent bowel movements, you're fat..
There are many warning signs of pregnancy. Some warning signs include tingling nipples, spotting, cramping, morning sickness, swollen breasts, a missed period, and/or darkened nipples.
Warning signs are usually a sign that something will be or has the possibility of occurring. They are also called symptoms when dealing with sickness.
There are many warning signs that you are experiencing a lack of oxygen. Some warning signs can include skin that is bluish to gray in color, lightheaded feeling, and tingling in extremities such as fingers or toes.