Fact of Listeria invasion and food poisoning

Food poisoning is usually mild, but sometimes causes deadly illness. There are two types of food poisoning: infectious agent and toxic agent. Food infection refers to the presence of bacteria or other microbes which infect the body after consumption. Food intoxication is the ingestion of toxins contained within the food, including bacterially produced exotoxins. Symptoms include nausea, vomiting, abdominal cramping, and diarrhea that occurs (within 48 hours) after consuming a contaminated food. Depending on the contaminant, fever and chills, bloody stools, dehydration, and nervous system damage may follow. These symptoms may affect one person or a group of people who ate the same thing (called an outbreak).

We always don’t become ill even we eat food that was exposed to harmful bacteria. But there was risk of being eating that food for regular diets. Different studies by professor Collin hill (University College Cork) shows bacterial invasion and their survival inside human body that helps to understand that why food poisoning is not so often even with contaminated diet. pH is the main factor that is hurdle in the growth of bacteria, acidic conditions in the stomach and gut will kill most microbes found in contaminated food.

Study has revealed that Listeria bacteria can overcome harsh acidic conditions by exploiting key food ingredients. Food constituents such as the amino acid, glutamate, can help the bacteria neutralize acid, allowing the bacteria to survive inside gut. Listeria that survives is able to cause serious and sometimes fatal infections.

 "People who consume foods that are contaminated with Listeria and are also high in glutamate, such as soft cheese or meat products, have a higher chance of developing serious infection than someone eating the same quantity of bacteria in a low-glutamate food,” Hill explained.

Listeria can also take advantage of food processing and storage conditions to help them survive.

"Bacteria which are exposed to low pH before entering the body may adapt to become more acid-tolerant and therefore better equipped to deal with acidic conditions in the body. For example, Listeria contaminating naturally acidic foods such as cheese may be more likely to cause infection than Listeria carried at a more neutral pH in water.