Does all microorganism survive to cooking?

Pathogens do not survive cooking temperatures above 65 ° C

Cooking food often has a sanitizing function and eliminates the presence of potential pathogens. The effects vary depending on the type of cooking used and therefore the degrees applied. Thus, maintaining more than 65 ° C in the food piece, for more than two minutes pathogenic microorganisms such as Salmonella sp., Shigella sp., Escherichia coli … are destroyed. And here’s a very important nuance: the temperature should reach around the food, even in the center (considered thick pieces such as roast beef).

Microbial growth is closely linked to temperature. It is therefore very important to maintain the hot chain (cooking-reheating-hot holding) to ensure that food is safe.

Raw foods like meat, fish, whole eggs or raw vegetables usually contain pathogenic bacteria as a result of soil contamination or due to the preparation process. Cooking is one of the most effective measures to avoid them. Besides giving food organoleptic characteristics as color, taste or texture, cooking also has a sanitizing function. The effectiveness of this process depends on the type of cooking, as it is not the same boil to fry two procedures in which the temperatures reached are different.

• Boiled. In the case of boiling foods, they reach temperatures of about 100 ° C. The boiling time large pieces of food should be at least 30 minutes. Water boils at a temperature of 100 ° C, which is maintained constant during boiling.

• Fry. When food is fried, they reach temperatures of between 180 ° C and 300 ° C. By immersing food in oil crispy product is obtained. It is important to choose oil, avoid frying large quantities at a time and check the food is as dry as possible when fried. The oil must be clean.

• Roast. The cooking is done with dry heat (oven or similar). The food is placed on a surface and receives heat evenly. Meat, fish and vegetables are the foods that are cooked in the oven.

• Microwave. With this appliance, food is heated by the rapid movement of the molecules of water, fat and sugar. The contact of these molecules in the form of friction heat is produced. One aspect to consider is that this kind of heat is not uniform and, therefore, may be cold spots where bacteria survive.

In most of these processes (except in the microwave), it should be noted that a gradation of the temperature, ie, this decreases when food is introduced (both oil in water) occurs, forcing ensure that the entire volume of the food reaches a minimum degree.

Keep in mind three very important points as exclusions:

The first is that cooking food destroys almost all pathogenic bacteria, whenever we speak in normal bacteria in raw meat ranges. So if a piece of meat is not thawed or cooled properly will reach such a high bacterial range that will not be sufficient heat treatment in normal conditions of time and temperature for that food does not have a concentration of infectious microorganisms.

The second is that there are exceptions to this rule and there are toxins produced by microorganisms resistant to heat treatment, as the example of botulinum toxin produced by Clostridium botulinum or producing Staphylococcus aureus.

The third issue is that we have to do too much cooking, or excessive temperature, can be hazardous. Therefore, it is essential to strike a balance between too little cooking and excessive who burns. When in a frying it exceeds the temperature, the product is burned or charred if more time than is necessary is allowed. Overcooking favors the creation of toxic substances such as heterocyclic amines and rich in starch (bread, cereal or crackers) foods, may result in the formation of acrylamide.

In the case of cooking food on a barbecue, excess temperature can produce polycyclic aromatic hydrocarbons such as benzopyrene. These compounds have mutagenicity and are formed during the preparation of food at elevated temperatures, especially if there is direct contact with the flame. In this case, it is advisable to avoid direct contact of the food with the fire and the cooking is done with the coals.