With the progress of the times and the improvement of quality of life, people are now paying more and more attention to food safety, and we all want to eat healthy and reassuring food. Therefore, under the catalysis of some media opinion, food preservatives have become the target of public criticism. Many people will think that preservatives are "poisons", and eating foods with preservatives will damage health.
In fact, over the years, food preservatives have been wronged by everyone.
A badly accused preservative
When it comes to preservatives, people tend to think they are harmful. Actually, this is a big misunderstanding.
Let's first be clear: broadly speaking, any substance is toxic, and talking about toxicity without dose is hooliganism.
Even the water and oxygen that are indispensable in our lives can cause water poisoning and oxygen poisoning when given adequate doses!
Preservatives are no exception. Our country has set strict standards for the use of food preservatives, including the scope of use and safe dosage. A preservative stands out from countless substances with antiseptic effects and becomes a "statutory preservative" approved for use, behind which there are countless studies on toxicology and metabolism to support its safety.
It can be said that for normal adults, these preservatives are completely safe without exceeding safe doses and do not affect health.
Then someone will ask:
I eat a lot of food every day, and if the preservatives of each food are added together, will it exceed the safe dose?
Don't worry, this issue has long been taken into account when national standards are formulated. The standard is set to consider the proportion of each food in the daily diet, and then add up the maximum allowable content of preservatives, if this is still far below the safe dose, before it can be formally established as a standard.
So what if unscrupulous traders ignore standards and indiscriminately add preservatives?
If this is the case, it can indeed be a health hazard. But you know: the cost of preservatives is not low, if not excessive can achieve antiseptic effect, then why overdose? Unscrupulous traders are not fools.
Moreover, if the food raw materials themselves are unhygienic and the food has been seriously contaminated by microorganisms, it is useless to over-add preservatives - preservatives usually can only inhibit microbial reproduction, and cannot sterilize.
In fact, many of the preservatives that are widely used now are naturally occurring, but we use the methods of the chemical industry to manufacture them in large quantities.
For example, the commonly used preservative benzoic acid is naturally present in blueberries and cranberries; while another preservative, sorbic acid, is present in many vegetables and fruits, which can be regarded as an unsaturated fatty acid, which will be decomposed into carbon dioxide and water like other fatty acids after being metabolized by the human body.
Why does food spoil?
As the name suggests, preservatives are substances that prevent food from spoiling. So, why does food spoil and spoil? This brings us to microbes.
Microbes are ubiquitous in the daily environment, and of course there will be a certain amount of microbes in the food we eat.
These microorganisms usually do little harm to us, but if the environment of the food is just right for them to grow and reproduce, after a period of slow growth, they will suddenly multiply in large numbers and produce a series of toxic substances. After people eat this spoiled food, they will have diarrhea, vomiting and even more serious symptoms of food poisoning.
A long shelf life does not mean that preservatives have been added
Since food can be affected by microorganisms to rot and deteriorate, does all food have to be added preservatives?
This is not necessarily true, some foods come with a "non-deteriorating" aura, there is no need to add preservatives.
1. Food is not suitable for microbial survival
As I said, only if the environment of food is suitable for the growth and reproduction of microorganisms, it is possible for microorganisms to breed in large quantities. So, some foods, their environment is not suitable for microbial survival at all. Such foods do not add preservatives, and the shelf life can also be very long.
Case in point: honey.
Its main ingredients are sugar – glucose and fructose – and are almost water-free. Bacteria in such an environment, due to osmotic pressure, will lose a lot of water and then dry to death - just like using salt to kill insects. In this way, honey can be easily stored without any preservatives.
For example, many dried goods - such as dried meat, dried fish, as well as coffee powder, milk powder, and even instant noodles, etc., their own moisture content is pitifully small, microorganisms can not survive at all, so they can also be stored for a long time without deterioration.
Therefore, the environment of high sugar, high salt and lack of water is actually a natural preservative.
However, please note that if these foods are exposed to the air for a long time, they may absorb moisture from the air. The more water is absorbed, the minimum living conditions of microorganisms (especially mold) may be reached. Therefore, we must pay attention to sealing and preservation to prevent food from absorbing moisture and causing deterioration.
2. Food has been occupied by "good microbes", and "bad microorganisms" cannot come in
Some foods themselves are obtained through fermentation, and the food is full of dominant strains, and other strains cannot "camp" here at all.
Case in point: yogurt
Lactic acid bacteria in yogurt account for the vast majority, even if there are miscellaneous bacteria, it is difficult to survive in this environment full of lactic acid bacteria, let alone breed. Therefore, yogurt does not need to add preservatives.
However, after the yogurt is left for a long time, the lactic acid produced by lactic acid bacteria accumulates in large quantities, which will seriously affect the taste. Moreover, if it is left too long, the lactic acid bacteria are dead, and other microorganisms may "take advantage of the void". Therefore, the shelf life of yogurt generally does not exceed one month, and it needs to be refrigerated. (Except for ambient yogurt, which we will explain in detail later)
3. The food has been sterilized
Some foods have killed all the microorganisms before they are sold, and after sterile packaging, the environment in which the food is located can be almost free of microorganisms. In this way, the food can naturally be left for a long time without spoiling.
Example: ULTRA-high temperature sterilization (UHT) treated milk
This milk is left above 135 °C for 1 to 2 seconds before packaging, killing almost all microorganisms. Therefore, ultra-high temperature sterilized milk, stored for a year is no problem, naturally it is necessary to add preservatives.
However, there are two sides to everything, and doing so will also have a certain impact on the taste and nutrition of milk.
The same is true of ambient yogurt. This yogurt is heat treated before leaving the factory to kill all the lactic acid bacteria. In this way, the processed yogurt can be left at room temperature for a long time without any change in taste, but because there are no lactic acid bacteria, the health benefits may be compromised.
Why add preservatives? In a word, for food safety.
If all aspects of a food are suitable for the growth and reproduction of microorganisms, but not completely sterilized, the addition of preservatives is the best way to extend the shelf life and ensure food safety.
For example, potassium sorbate is added to some juices as a preservative. Some people will ask, why not do UHT sterilization?
This is because the juice will lose a lot of nutrients after ultra-high temperature sterilization, and the taste will change greatly. Potassium sorbate, as a safe preservative, does not endanger health as long as the dosage meets the regulations.
After weighing the pros and cons, it makes sense to use preservatives.
For example, sodium nitrite is added to many processed meat products, such as ham, lunch meat, and canned meat products.
This substance is not only a preservative, but also a coloring agent. Meats with sodium nitrite will be more rosy in color and will look better. Of course, that's not the point.
A very important reason for the addition of sodium nitrite is to inhibit the growth of Clostridium botulinum. Botulinum toxin secreted by Clostridium botulinum is the most toxic substance known, and if food is contaminated by this bacterium, people may be poisoned after eating it - and even life-threatening when it is serious!
Therefore, in order to prevent the risk of botulism, it is not difficult to understand adding sodium nitrite to these foods.
Not adding preservatives is not necessarily healthier
Walk around the supermarket, there is a lot of publicity about "no preservatives". Is food without preservatives healthier? Not necessarily.
The first is the issue of security.
If a food should have been fortified but not added, then eating this food is quite dangerous.
For example, if nitrites are not added to canned food, there is a risk of botulism after eating. From this point of view, preservatives actually make a great contribution to ensuring food safety.
Then there's the issue of health.
Whether the food is healthy or unhealthy has nothing to do with whether preservatives are added.
For example, many fried instant noodles don't have any preservatives added to them, but that doesn't stop them from being high-fat fried foods.
For example, in order to "do not add any preservatives" publicity, some merchants add a lot of salt and sugar to food instead of preservatives. Such food is not only not healthier, but also affects the taste of food.
summary:
Preservatives are not "poisons" and will not harm health as long as they are used normally. In a sense, it could even be said that without preservatives, we may not be able to buy as much safe food on the shelves.
Rather than "talking about preservative discoloration", people should pay more attention to how to eat a reasonable diet and balance nutrition.