Food hygiene seeks to eliminate the development of microorganisms that can affect our health. As explained in a statement by Isabel García Jalón, director of the diploma program of Human Nutrition and Dietetics at the University of Navarra, "the elderly should take special care to consume safe food because they are more sensitive to pathogenic microorganisms. Other risk groups are pregnant women and the immunocompromised".

Professor García Jalón gave a lecture at lecture at the University of Navarra on 'Food safety', at a workshop on "The challenges of the 21st century consumer. Women and health", organized by association provincial of housewives, consumers and users of Navarra 'Santa María la Real'.

"Microorganisms are the main cause of illnesses linked to food consumption. This is because they are more difficult to control than other risks, such as those produced by additives or environmental contaminations, cases in which health authorities grant certain levels of permissiveness," he said.

Isabel García Jalón, professor in department Microbiology at the School of Science, stated that "the greatest danger is that the issue harmful microorganisms present in food increases to dangerous levels by the time it is consumed." At home, this can happen "with prepared foods that have been handled further (seafood cocktail, salad with pieces of ham or cheese...) and those left at room temperature for a few hours." In this regard, she recommended using clean utensils and storing the food in the refrigerator until ready to eat.

In the case of technologically processed and ready-to-eat products, "there can also be danger when cold storage is interrupted for hours, for example, if they are kept in the car or out of the refrigerator for a long time after purchase". The professor cited the recent outbreak of contamination in France by Listeria monocytogenes, which arose in vacuum-packed cold cuts preserved at insufficiently low temperatures. This case seriously affected at-risk groups and even caused some deaths.

The expert from the University of Navarra recommended not to rely exclusively on the appearance of food: "Pathogenic microorganisms can be found in sufficient quantities to damage health, without having altered the texture, color or flavor of the product". The foods most susceptible to the growth of microorganisms are protein foods, those rich in water and non-acidic foods such as meat, eggs or fish. In general, a cooked product should not be kept in the refrigerator for more than 48 hours.

As for freezer storage, there is no problem if temperatures are low enough. "Regarding freezing and thawing, the problem, more than hygiene, affects the gastronomic and nutritional quality. Repeated freezing damages the structure of the product, dries it out and loses components".