Human Digestion: Processes, Health, and Food Safety
Chewing
During chewing, food is fragmented, and its presence in the mouth stimulates the secretion of saliva (which moistens and lubricates the food bolus) by the salivary glands.
Swallowing
Once the bolus is crushed and insalivated, it passes from the mouth into the esophagus. This act is called swallowing. Swallowing is a voluntary phase, in which the tongue pushes the bolus against the palate and elevates the soft palate, and two involuntary phases: the first, when the bolus passes into the pharynx, and the second, when waves of contraction start, driving it into the esophagus (peristalsis).
The Processes of Chemical Digestion
In the Mouth
The salivary glands secrete saliva. It contains mucus that lubricates and moistens the food bolus. The saliva has an enzyme called amylase, which starts the chemical digestion of starch.
In the Stomach
Glands in the wall of the stomach produce digestive juices. These contain hydrochloric acid and the enzyme pepsin, which digests protein. Also, they secrete mucus to protect the gastric walls from this intense chemical attack.
In the Small Intestine
The liver pours bile, which aids digestion of lipids. It also diverts the pancreatic juice and intestinal juice (secreted by the cells of the intestinal wall), whose enzymes complete the digestion of starch and protein.
Digestive Care
For the digestive tract and related organs to function properly, you need to follow certain rules about health and hygiene. In this way, you can prevent some diseases, like tooth decay, obesity, and food poisoning.
Digestive Health Habits
To care for your digestive system, heed the following advice:
- Wash hands properly before eating. Washing hands prevents the contamination of food with bacteria or parasites (if you’ve been playing with your pet).
- Wash fruits and vegetables to be eaten raw. They should be left in water (three drops of bleach per gallon of water) for about 20 minutes. Then, rinse with water 2 or 3 times, in this way, remove the traces of pesticides and land.
- Avoid eating very hot or cold foods. Cold foods can irritate the throat and encourage the emergence of pharyngitis or tonsillitis. Very hot foods can cause burns to the mouth and esophagus.
- Chew food thoroughly. This will help you have good digestion and avoid choking.
- Take care of teeth and tongue. After dinner, brush your teeth and tongue, and regularly visit your dentist.
First Aid
Choking
Occurs when a piece of food or a foreign body gets stuck in the esophagus and presses the epiglottis, preventing breathing. Choking produces numerous deaths by suffocation. In adults and older children, you can proceed by performing the Heimlich maneuver, which is firmly pressing on the abdomen below the diaphragm so that this muscle rises and forces the lungs to create an artificial cough, whose air pushes up food or the foreign object blocking the airway.
Dehydration
It is the lack of body fluids needed for the body to carry out its functions optimally. Mild dehydration can be treated with alkaline lemonade, which is obtained by dissolving in a quart of water the juice of 2 lemons, half a teaspoon of baking soda, half a teaspoon of salt, and two tablespoons of sugar.
Food Preservation
Physical Methods of Preservation
Heat Conservation
Treatment with high temperatures for a few seconds eliminates or reduces the number of bacteria.
- Sterilization or UHT treatment is a process in which foods are subjected to a temperature of 135ºC for 2 or 3 seconds to destroy all microorganisms. The advantage of this method is that the products thus treated are kept longer.
- Pasteurization involves heating foods to 72ºC and then cooling them quickly. In this way, it reduces the number of microorganisms in sufficient quantity so that food is not altered.
- Canning is a heat treatment in which the food is closed hermetically in a container that is immersed in water at high temperatures. The food thus treated can be stored for several years.
Cold Preservation
The cold slows or prevents the growth of bacteria. Perishable foods are kept for about 5 days if kept between 0ºC and 4ºC, and several months if frozen at -20ºC.
Food Dehydration
Sun drying removes salt and water from the food and prevents the proliferation of microorganisms. Freeze-drying involves freezing the food at -80ºC and subsequently submitting it to a vacuum to remove water.
Chemical Methods of Conservation
Using Preservatives
These prevent microbial growth in food.
Employment Acid
There are foods that can be stored under acidic substances. You can also let an acidic fermented food by the action of certain bacteria.
Food Additives
Food additives are substances added to food and food preparations that retain their properties, recover lost qualities, and avoid decomposition.
Categories of Food Additives
- Acidifying: Used to acidify the food and prevent the development of microorganisms.
- Antioxidants: Prevent fats from oxidizing and acquiring a bad odor and taste like rancid.
- Emulsifiers: Are substances used to disperse a substance into another with which it is miscible.
- Coloring: Returned to its original color or food color added to products that do not.
- Preservatives: Prevent or hamper the development of microorganisms.
- Powers of flavor: Are substances that enhance the flavor of a meal.
How Food Can Be Contaminated
Foods are perishable products that are altered by natural decay and contamination by parasites, fungi, and bacteria, toxic substances (toxins) that the latter produce, and other chemicals.
Food Contaminated by Bacteria
These foods, when ingested, cause food infections. When the food contains toxins, such infections are known as toxic infections.
Food Contaminated with Toxins
The intake of these foods causes poisoning.
Food Contaminated by Chemicals
Generally, it is an accidental contamination. Sometimes it results from a misapplication of pesticides, which leave residues in fruits and vegetables.
Precautions for Consumers
When we consume, we must take certain precautions:
- Highly perishable foods should be eaten as soon as possible due to easy contamination.
- Frozen foods should never be refrozen again.
- Engineered foods should be eaten immediately.
- Before using the vegetables, they should be soaked for half an hour in water with drops of bleach and then washed with water.
- The fruit should be peeled or thoroughly washed to remove pesticide residues.
- The meat should be eaten well cooked to prevent food-borne infections.
- The cans do not have to be dents or curved. Also, if gases are open, it is very likely to contain botulinum toxin, so it should be disposed of.
Malnutrition
Malnutrition is poor nutrition, due either to poor nutrition or overeating.
Deficiency Diseases
Vitamin deficiency diseases are called avitaminosis. Our body cannot synthesize vitamins. In some cases, it may build one or more vitamins, and the body cannot eliminate them. Occurs, then, hypervitaminosis or vitamin excess.
Obesity
It consists of an excess of body fat. People are obese if the amount of fat exceeds 15% by weight in men and 25% in women. It occurs when we consume too much energy as carbohydrates and fats. You can also have a genetic origin. To do exercise and not eating fats and carbohydrates in excess.
Anorexia
It consists of malnutrition and emaciation, caused by the rejection of food due to psychological disorders. Anorexics self-impose a severe weight loss diet because they are obese if they are not really.
Bulimia
It is another condition of loss of control over food. People who have also taken very strict weight loss diets but break giving true attractions. This creates a feeling of guilt, and they make themselves vomit to prevent weight gain. Bulimia causes serious health disorders.
Food Additives
Food additives are substances added to food and food preparations that retain their properties, recover lost qualities, and avoid decomposition.
Categories of Food Additives
- Acidifying: Used to acidify the food and prevent the development of microorganisms.
- Antioxidants: Prevent fats from oxidizing and acquiring a bad odor and taste like rancid.
- Emulsifiers: Are substances used to disperse a substance into another with which it is miscible.
- Coloring: Returned to its original color or food color added to products that do not.
- Preservatives: Prevent or hamper the development of microorganisms.
- Powers of flavor: Are substances that enhance the flavor of a meal.