The researchers compare the chlorine rinse with irradiation with ionizing radiation, and show that it is able to kill bacteria that rinses do not harm
Washing fruits and vegetables before eating them reduces the risk of food poisoning and contracting intestinal diseases. At the same time, new research shows that washing the vegetables - even with disinfectant chlorine - does not achieve the goal, and some bacteria are able to survive the washing. The researchers compare the chlorine rinse with irradiation with ionizing radiation, and show that it is able to kill bacteria that rinses do not harm.
Many studies show that certain disease-causing bacteria are able to hide from washing with chemicals. The bacteria can migrate into the leaves of lettuce, spinach and other vegetables and fruits. The soap and disinfecting chemicals, which only reach the surface of the plant, cannot harm the bacteria hiding inside the leaves themselves. In addition, some bacteria are able to organize themselves in dense colonies that cover the fruits and vegetables and protect the bacteria. Such bacterial colonies may contain many types of infectious and disease-causing bacteria, such as salmonella and E. coli.
Now scientists from the United States Department of Agriculture suggest that irradiation can be used as a means of killing pathogens (disease agents) that normal chemicals cannot reach. In the irradiation process, the food is exposed to electron beams that create positive and negative charges. The result is severe damage to the genetic material of the living cells, which leads to the paralysis of parasites and the killing of bacteria and insects that have penetrated into the food.
The issue of food sterilization has recently received a lot of attention in the United States, due to the increase in the last decade in the number of infections of fruits and vegetables, and the diseases caused by them. Out of all those cases, the big 'spinach outbreak' in 2006 particularly upset the public in the USA. 205 people contracted intestinal disease due to E. coli contamination of fresh spinach, and three died. After the outbreak, public health officials had to ask themselves how the bacteria survived the various treatments the plants underwent.
Already at that time, studies proved that disease agents such as salmonella and E. coli can be absorbed into mature fruits, and are also able to migrate into them while the fruit is growing and ripening. The researchers decided that there was a need for a sterilization process that could also kill pests living inside the leaves.
Dr. Brendan A. Nyamira, a microbiologist at the United States Department of Agriculture in Windmore, led the research. Nyamira and his colleagues cut spinach and lettuce leaves and dipped the pieces in a mixture of E coli bacteria. The bacteria were sucked into the leaves using a special vacuum process and then the effect of three different treatments on the contaminated leaves was tested: washing with water, chemical washing and irradiation.
After the washings or irradiations, the leaves were crushed and the amount of surviving bacteria was counted. Not surprisingly, the study showed that washing with water alone was not effective in reducing the number of pathogens on the spinach and lettuce. Even the chemical treatment, by washing with a sodium hypochlorite solution, did not result in a significant reduction in the number of E coli bacteria on the spinach, and killed less than 90% of the bacteria on the lettuce.
Compared to the last two treatments, the screening significantly reduced the number of bacteria on the spinach and lettuce leaves. The level of elimination depended on the radiation dose applied to the leaves. Irradiation at the highest dose killed 99.99% of the bacteria on the lettuce and 99.9% of the bacteria on the spinach.
The researchers then tested how salmonella and E coli bacteria colonies cope with radiation. They found that the colonies containing Salmonella bacteria tend to die following the irradiation, while the colonies containing E. coli are more immune. Nyamira says that, "In the most immune cases, we saw a difference of a few percent, but there is no comparison at all to immunity to chemical treatment."
Despite the great interest in the subject, Nyamira says that it is still unclear whether the pathogens are actually capable of multiplying within the plant tissues, or just surviving in the contents. "This is an important question, because if the pathogens do not multiply efficiently inside the protected spaces and maintain a small population, then they are less dangerous to consumers," he says. "If they are able to multiply inside the plant tissues, then they could be more dangerous."
Despite the approvals given for screening, there is still concern among some of the public about the chemical changes that the food undergoes in the process. Opponents of screening claim, among other things, that screening also creates substances harmful to health, such as formaldehyde and benzene.
However, according to Dr. Kristin Baron, consumer trust in screening has been building over the years when studies have proven the effectiveness of screening in preventing the transmission of diseases through food. Doctor Baron, who examines consumer claims in matters of food safety and quality at the University of California-Davis, says that, "Sixty to 90 percent of consumers determine that they will buy irradiated food, after being informed of the benefits of the process and its approval by the authorities."
In the end, it is possible that the choice - to wash or to radiate - will be up to the consumer alone.
5 תגובות
Sterilized food is for mentally sterile slaves
Then the sterile food is served by a waiter who spits on the food, a cook who didn't wash his hands, a mouse who walked and even took a bite of the sterile vegetables (on second thought it should be the mouse, he got to eat the food in its cleanest state)
The plants are weak because the soil is weak due to illogical agriculture without a fallow year or rotation of the growing areas, because of this the plants are not able to fight pathogens and neither are we
This is a type of research that is disconnected from real reality. The real reality is that, after a hundred years in which man caused an ecological disaster on a global scale, the bacteria are the secondary problem in this story. There is a screening that will never solve the problem of man-made toxic substances found in vegetables and fruits.
Even under the current sanitation conditions in the western world, poisoning from bacteria in vegetables and fruits is rare and death is even rarer.
However!
How will you get the DDT out of the sterilized tomato?
All this sterility is harmful to the body and the body will become weaker because it deals less well with bacteria, and we have already seen studies that have proven this. It is enough to wash fruits and vegetables in a little water, not chlorine or irradiation.