Europeans use nine ways to determine if the chicken is cooked, but most of them are ineffective and dangerous — the color of the meat does not reflect the extent of its availability, and when checking with a thermometer the temperature of internal part of chicken can miss bacteria that will survive on the surface. The fibrous texture of meat and the lack of smooth pieces was a good measure of the degree of doneness, but this method is difficult to formalize specific instructions. The authors of the work published in PLoS One, recommend the use of thermometers and several times to measure the temperature in different parts of the meat, including the thickest area on the surface.
In poultry meat can contain bacteria-causative agents of intestinal infections. Five percent of the broilers find Salmonella, and 38 percent Campylobacter. Therefore, improperly cooked meat can cause outbreaks of salmonellosis or campylobacteriosis. Various health organizations suggest to make sure that the chicken was not pink sections, test the opacity of the juice and warm the meat up to at least 70 degrees Celsius. Latest recommendation the most common, so check the readiness of meat with a kitchen thermometer is considered the most reliable. However, the effectiveness of even this method has doubts, and under advice to evaluate the color of meat and juices there is no scientific evidence.
Norwegian scientists under the leadership of Langerud Solveig (Solveig Langsrud) from the Norwegian Institute of food explored the ways in which Europeans check the readiness of the chicken. The researchers acquainted with how to cook chicken in 75 families in five European countries. Participants were interviewed, and then a few times watched the process of cooking at home and recorded it on video.
Scientists have identified nine of the ways people determine when the chicken is done; in most cases used more than one method at the same time. The most common way to cook a chicken within a certain time specified in the recipe or derived from my own experience. Many participants pointed out that if too long to heat up the chicken it will become dry and tasteless, and the excessive security in this case is contrary to hedonistic goals.
About half of the participants evaluated the readiness of the meat by the color of its surface, as many people cut the meat to ensure no pink inside the parcel. Another popular method is to monitor the texture of chicken. Meat is pierced, pressed and cut, to feel the extent of his resistance, however, none of the participants could not articulate specific criteria for the texture of cooked chicken.
In many households it is customary to heat the chicken more than once: for example, first fry and then stew, or cook. In several cases, the readiness of meat is determined by taste, smell and even sound. And only one participant, 70-year-old Norwegian, used the thermometer.
The second part of the study was to in laboratory conditions to test the security of common methods of evaluating the readiness of the chicken. In the chicken fillets were injected with a mixture of bacteria of the genera Salmonella and Campylobacter, and then cooked on the grill. The meat needs to heat when the internal temperature reached a certain level according to the thermometer. Prepared for 11 samples of five final temperatures from 50 to 70 degrees Celsius; set the texture and color. Crushed samples of meat and scrapings from the surface were grown on agar to estimate the number of surviving bacteria.
The time required to heat the meat to a certain temperature, greatly varied even in strictly controlled laboratory conditions (e.g., 70 degrees was reached for 19-26 minutes), so you focus solely on the cooking time in the home is not worth it.
When heated to 70 degrees the number of living bacteria was reduced by four to five orders of magnitude, what that level of death of campylobacteria reached already at 65 degrees, but to kill Salmonella was more difficult. On the outer surface of the fillet, which is not in contact with the grill, the number of bacteria was reduced by only three orders of magnitude when the depth of the chicken was heated up to 70 degrees. The authors note that when cooking you need to take care of a uniform surface treatment of meat is not less than its inner part.