LA CONSERVACIÓN DE ALIMENTOS

La comida sufre el ataque destructivo de ciertos agentes que la estropean, con lo cual se hace necesario utilizar métodos de conservación que eviten este proceso de deterioro. Algunos de estos sistemas para mantener los alimentos en buen estado se emplean desde hace mucho tiempo, aunque han sido mejorados a lo largo de la historia e incluso se han creado nuevos métodos.

Una de las ventajas de estas formas de tratar los productos alimenticios supone conseguir cualquier comida a lo largo de todo el año y no tener que
esperar a una época concreta, ademas de ofrecer la posibilidad de guardar los alimentos cuando no se van a consumir en el momento.

ATAQUE DE DESTRUCCIÓN

Bacterias y hongos destruyen los alimentos, que también se descomponen por las enzimas que contienen. El oxígeno estropea la grasa y destruye la vitamina C de las frutas y verduras.

SECADO
MICROORGANISMOS

AHUMADO
El humo posee sustancias químicas que destruyen las bacterias.

Se elimina el agua que necesitan los microorganismos.

SALAZÓN
Una solución de sal común impide la multiplicación de las bacterias.

INFLUENCIA
ENZIMATICA

PRODUCTOS QUÍMICOS
Al añadir ciertos productos se impide la fermentación de los alimentos.

Oxígeno

CALOR

FRÍO

El calentamiento destruye los organismos de los alimentos.

Las bajas temperaturas frenan el proceso vital de los microorganismos.

INFLUENCIA QUÍMICA

Producto concentrado. Ejemplo: leche vaporizada

8

AULA

DE EL

Aire

Polvo.
Ejemplo
Leche en polvo

Calor

MUNDO

Torre de pulverización

Batería de enfriamiento

PULVERIZACIÓN
ENSECO

PLACAS

Unidad de enfriado

Camara de secado

TÚNEL DE
CONGELACIÓN

AIRE

MEDIOS PARA CONGELAR
Existen diferentes sistemas que se utilizan habitualmente para congelar:
One of each four (24.5%) between 5 and 64 years eat junk food every week. The people between 14 and 30 years have the highest rate and the consumption is higher in the urban areas. Another problem is the high consumption of soda; one of each five consume soda per day and one of each two per week. Finally in Colombia the consumption of candies is high. One of each 3 Colombians consumed dialy. 17.8% consume two or more times per day. The consumption is 12 percentage points bigger in the urban areas in comparison with rural areas

2.2 Breastfeeding and supplementary feeding.
In Colombia, 96% of the women start to breastfeeding their newborns and a little bit more of the half of the women does this practice in the first hour. In that practice the country had an improvement in the last 5 years (2005:49% 2010:56.6%). Nowadays the total duration in months of breastfeeding is 14 months, since 2005 that rate do not improve. The women who live in rural areas and with a low level in SISBEN breastfeed her children more time. The introduction ofsupplementary feeding start between 6 and 8 months. In the supplementary feeding of children under 3 years the most common foods are water, juices, agua de panela( traditional drink) and protein sources as beef, poultry, fish, egg. The consumption of fruits and vegetables is not common.

3. Nutritional deficiencies. The information that had National importance is taken from the National survey on Nutritional status Colombia (2005) (2010) (ENSIN 2005) (ENSIN 2010) and also the data that comes from the National survey on demography and health (ENDS). In these surveys the country was divided in 7 regions. East, Central, Pacific, Bogota, Orinoco and Amazon. SISBEN levels are used and those are related with the socio-economical capacity of the people.

3.1 Children under 5 years:
Those surveys show that the percentage of Chronical Malnutrition is about 13.2% that in an International level is considered as low prevalence. Between 2005- 2010 the reduction was about 17%. That leaves Colombia to 5.2% percentual points to accomplish the goal that was propose for the country in the objective of the development of the millennium to reduce the chronic malnutrition in children less than 5 years to 8.0%. The major proportion of chronic malnutrition are in the people that is in the 1, 2 level of SISBEN, in children with mothers that had less level of education and that lives in the Atlantic, Amazon Orinoco and Pacific region. The data showsthat Colombia is in the third pace of lower prevalence in Latin American countries.

3.2Children between 5 and 17 years:
The situation between the children of 5 years and 17 years shows an improvement; the growth retardation decrease 28%. Nevertheless 1 of each 10 children and teenagers between at those ages has retardation in growth. The high prevalence is in level 1 of SISBEN (13.4%), in children with mothers that does not have education (24.1%). In the rural area the prevalence is double in comparison with the urban area (15.2% vs. 7. 9). The departments with more problems are located in the Pacific and Amazon region. On the other hand the prevalence of obesity has increased a 25.9%. One of six children and teenagers
presents overweight or obesity and this relation increase with increasing the level of SISBEN and the educative level of the mother (9.4% for mothers without education and 26.8% with mothers with high education). In the urban area the percentage is about 19.2% and in the rural area about 13.4%

3.2 Adults (18-64 years
An increase in the weight of adult population is obtained in the surveys. One of two Colombians has overweight. The data shows an increase of 5.3 percentual points (2005: 45.9% and 2010: 51.2%). Is more common in females (55 % vs 45.6%). All the levels of SISBEN show high prevalence that is over 45%. The proportion is the same for all the departments and the prevalence is higher inurban areas (52.5%) that are over the national mean.

3.4 Anemia
One of each 6 children between 1 to 4 years and 1 of 6 pregnant women of the sample has anemia; this proportion is of 11% in teenagers between 13 and 17 years. Is frequently t in rural areas and in the population that is classified in 1 and que el aire frío absorba el calor, que la mercancía se introduzca en un líquido frío (congelación por inmersión) o que el producto se ponga en contacto con una superficie fría (placas).

FABRICACIÓN DE LATAS DE CONSERVA
Los envases de conservas se fabrican con una chapa de hojalata y mantienen un cierre hermético que se consigue gracias a los pliegues que unen la tapa y el fondo con la lata.
IMPRESIÓN

LÍQUIDO

Calor

Los alimentos colocados en estantes se introducen dentro de un túnel automatico donde una corriente de aire frío los congela para su conservación.

CHAPA

Agua

La carne congelada se coloca en una camara de secado cerrada herméticamente al vacío, lo que provoca una baja presión. Al calentarse las estanterías, el hielo del alimento se evapora y se transforma después en agua.

Carne

La leche concentrada
(45% seca) se
esparce en gotas
muy finas por la parte
superior de la torre de
pulverización, se seca
al encontrarse con el
o
aire caliente (200 C) y
cae después en
forma de polvo al
fondo de la torre.

Ventilador

LIOFILIZACIÓN

Vapor de agua

MATERIA
PRIMA MAS
COCCIÓN

CONSERVACIÓN
TAPADO

CORTE DE TAPAS Y FONDO

Las latas llenas se
cierran, se
calientan para
matar los
microorganismos y
finalmente se
enfrían.

TAPA

CORTE DEL
ARMAZÓN
Infografía: Juan Emilio Serrano
Textos: Manuel Irusta / EL MUNDO

SOLDADURA DE
LA LATA

COLOCACIÓN
DEL FONDO
CALENTAMIENTO

ENFRIADO