Informe del Comité Científico de la Agencia Española de Seguridad Alimentaria y Nutrición (AESAN) sobre las combinaciones tiempo-temperatura necesarias para el cocinado seguro de los alimentos y las temperaturas adecuadas para el mantenimiento en caliente y recalentamiento de las comidas preparadas

Abstract

Thermal treatment plays an important role in destroying pathogenic microorganisms in food. For this reason, both the temperature at which foods are cooked and the duration (time) thereof, have a special impact from a food safety perspective. Another important aspect of food safety is the temperature for keeping cooked foods hot. Given that cooking does not inactivate spore-forming pathogenic bacteria, an inadequate temperature could lead to the microbial multiplication and, consequently, may constitute a risk factor. Most pathogenic microorganisms can grow in foods at temperature of between 5 and 60 ºC, the range of temperatures that is considered a potential risk. Refrigeration and subsequent reheating of cooked food before consumption are also factors to be taken into account. It is necessary to refrigerate as soon as possible, maintaining refrigeration at an adequate temperature and reheating at a sufficient temperature to inactivate pathogenic bacteria. Adequate refrigeration is essential to prevent the growth of spore-forming bacteria that have survived the initial thermal treatment. During preparation, cooking and storage of cooked foods, it is essential to maintain good hygiene practices, paying special attention to the cleaning and disinfection of utensil and equipment and to handlers. The recommended time-temperature combinations for cooking foods differ between different countries and institutions, much like the scientific publications. The Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) has reviewed the existing recommendations and analysed the effect of the temperature and time combination on the growth and destruction of the principal pathogenic microorganisms and parasites in different foods (meat, fishery products, eggs and egg products and vegetables). There is also reference, from a food safety perspective, to the cooking technique known as “slow cooking”. After this review, the Scientific Committee has proposed a series of time-temperature combinations for the cooking of meat, fish products, eggs and vegetables, considering the temperature to be reached in the centre of the product (coldest point). For the cooking of meat, it is recommended that a temperature of 70 ºC is reached in the centre of the food for at least 1 second (or equivalent treatment); for poultry it is recommended that that temperature be 74 ºC for at least 1 second (or equivalent treatment). For the cooking of fish, it is recommended that a temperature of 68 ºC is reached for at least 15 seconds in the centre of the product (or equivalent treatment); in the case of stuffed fish, the temperature to be reached in the centre of the product is 74 ºC for at least 15 seconds (or equivalent treatment). Raw molluscs should be cooked at 90 ºC for at least 90 seconds in boiling water (or equivalent treatment). The adequate internal temperature for the cooking of dishes containing eggs is 70 ºC for at least 2 seconds (or equivalent treatment), which is sufficient treatment to not require the use of pasteurised egg products, and they should be maintained at 8 ºC for a maximum of 24 hours. In the case of cooking eggs for immediate consumption, it is recommended that they are cooked so that the centre of the product reaches a temperature of 63 ºC for at least 20 seconds (or equivalent treatment). This recommendation applies to different egg-based preparations such as fried eggs and omelettes which, on daily basis, may not set completely (provided they are served for immediate consumption). For the cooking of vegetables, a combination of 70 ºC for at least 2 minutes in the centre of the product (or equivalent treatment) is considered adequate. A minimum temperature of 63 ºC is recommended for keeping cooked foods hot. If cooked foods are not to be kept hot, they should be refrigerated immediately, reaching a temperature of 4 ºC in 2.5 hours and should subsequently be maintained at 4 ºC or lower. For reheating cooked foods, a temperature of at least 74 ºC should be reached in the centre of the product for at least 15 seconds. From a food safety perspective, the use of leftovers is not recommended. However, where they have been cooled and refrigerated in adequate conditions, they may be reheated at a temperature of at least 74 ºC for at least 15 seconds in the centre of the product. If cooking or reheating using a microwave, the time necessary is longer than indicated in the above sections. All the above recommendations are applicable at all times provided that strict hygiene measures have been correctly applied and the previous stages have been carried out correctly (cooking, cooling, refrigeration).