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On the Safety of Canned Food

2016/10/26      view:

To make researches on food safety, the very first step is to study the food insecure factors. by far, domestic and foreign research scholars called them as the unsafe factors or harmful factors, which are divided into three broad categories, biological factors, physical factors, chemical factors, among them, biological factors are considered to be the biggest hazard factors of all, especially for processed foods, in order to eliminate the biological hazards, if improper methods were carried out, it is possible to increase the physical and chemical hazards during food processing.

For example, at present, in order to prevent food from microbiological hazards, chemical preservatives are being added to many processed foods, excessive use or abuse of preservatives undoubtedly will increase the risks of food chemical hazards. Thus, food safety for a certain processed food has everything to do with its processing technology, to some extent, food processing method determines the risk for food safety.

Currently, it is popular to perform level assessment of potential risks, so, among all kinds of processed foods, which kind of food has the minimum safety risk?

Food processing is the foundation of food commercialization, but it is also an expression of human civilization, it requires the assurance of food security under the premise of keeping food commodity characteristics to the maximum, such as nutrition, flavor, texture, and shelf life, etc. The shelf life of food is the most important commodity characteristic for processed foods. In order to prolong the shelf life or storage life of food, human has invented various food processing and storage methods long time ago, such as curing, drying, fermentation, freezing, etc. However these food processing and storage methods still cannot fully meet the needs of nowadays’ human social activities, more than 200 years ago, the French invented the canned food, which then developed and last till today and finally become a main form in the processed foods international trade.

Since the founding of Microbiology, any food processing and preservation must take the microbes into account, as it can cause food corruption and even food poisoning, therefore, food sterilization and antibiosis became a very important theory basis of all kinds of food processing and preservation. Chen Junshi, an academician of Chinese academy of engineering in the field of food safety constantly stressed that the worst effects of the current food safety still come from biological hazards, which mainly refer to bacteria and   toxins produced by bacteria.

Bacteria growth needs nutrition, water, preferable environment, temperature and pH condition, etc., according to their need for oxygen, they are divided into aerobic and anaerobic bacteria, most bacteria belong to aerobic bacteria in common environment. In order to effectively control food microbiological hazards FDA (USA) based on these characteristics, and water activity and pH value of processed foods,, divides processed foods into high acid food, acidification and low acid foods, and regulates that low acid food and acidification food from abroad all be required to get registration and got safety assessment, only after getting approval can they be exported to the United States market.

According to the properties of these bacteria, I divide the processed foods into two categories, one is sterilization processed foods, and the other is bacteriostatic processed foods.

This classification hasn’t been put forward yet by far, but actually, all the current market sales of processed foods can be included in it. FDA regulations have that, the processed foods such as water activity below 0.85, high acid foods, alcoholic beverages, fermented food etc, there is no need to register, actually they all belong to this kind of processed foods, which through controlling the bacteria to grow in food by bacteriostatic effect, this antibacterial way of processing also include salt curing, vacuum freeze drying, low temperature sterilization with food preservative added, etc.

According to the room temperature that food requires during commodity circulation process, processed foods thus can also be divided into Normal Temperature Food and Cold-chain Food. Cold-chain food is by controlling the temperature for the bacteria to grow to achieve the effect of inhibiting bacteria, which belongs to bacteriostatic processed foods; And processed foods in the normal temperature circulation, in order to achieve a long shelf life, the method commonly used is the combination of sterilization and bacteriostat. Sterilization or thermal sterilization is the most commonly used method, they can even kill bacteria spore, and normal pressure sterilization, it can kill inactivated bacteria under 100 degrees Celsius, and then through the control of pH value, water activity, as well as preservatives-adding to achieve the goal of prolonging shelf life. To analyze it from the perspective of security, as long as the food is processed in a way that follows the standard operation, thus the food safety can therefore be guaranteed. But there is always a need to set up safe level, or risk level. To lower the pH value, though effective, its application is limited somehow, and more than oftenin order to ease the discomfort from sour taste, make foods more tasty, it is necessary to add more sugar to adjust the proportion of sugar and acid. Since the ancient times, by sun-drying or pickling to reduce the water activity of antibacterial processing preserved food, these kinds of methods also have their limitations, after all, daily diets relied on pickled vegetables has been drifting away and with the current social development; besides, at present, the largest and most varieties of antibacterial type processed food that circulate on the market are the foods with preservatives.

According to experts, it is safe to use food preservatives in accordance with the provisions or regulations, but the experts also pointed out that the abuse of food preservatives can cause food safety problems. What is "abuse"?  Many foods with two or three kinds of preservatives added, though separately all meets national standards, but look from the anti-corrosion dose perspective, it can be understood as overdose, according to China's current standards, cases like this do not belong to the category of "abuse"; in another case, assume a preservative dosage exceed the standard, although just one single preservative is added, it will be convicted for "abuse". Those kind of provisions actually are hard to understand. At present a lot of processed foods are with two or more kinds of the preservatives added, let’s not talk about whether it belongs to "abuse" or not, but to believe that the risk of food safety must be lower than without any use of preservatives in food.

Concerns about the safety of food preservatives, I just make my judgement according to the normal logical that risks exist. First of all, the preservatives do have the inhibition effect on the bacteria, which is an indisputable fact, or else it can't otherwise be named as preservatives; Secondly, certain dose of preservative will not directly pose harm to our human body, this is a fact that we can also believe in. The question is: whether there is indirect harm? All kinds of bacteria in the digestive tract maintain ecological balance, human intake of processed foods containing preservatives, these preservatives must have bacteriostatic effect on the normal intestinal bacteria, therefore the balance in intestinal flora will be affected. Infer from this point, Intake of preservatives will lead to the risk of intestinal flora disturbance. The risk might be very low, but there must be. Here is the conclusion: The food safety level for processing food without preservatives added is higher than those with the use of preservatives.

To sum up, and I am glad to find that two major categories of processed food that LiXing company carried out is the safest. One is canned food, Canning is a method of preserving food in which the food contents are processed and sealed in an airtight container, there is no need to add any preservatives to get a long shelf life at room temperature; The other kind of food is Leisure food by vacuum freeze drying processing method, which is the typical product of combination of sterilization and bacteriostasis.

A large number of facts can also help to support the argument that " canned food is the most safe food" , by the end of 2015, and since the founding of nation, China's total canned food export volume is 50 million tons, the total exports amount is more than $60 billion, so far no major food safety incidents has occurred; Canned food is the earliest Chinese food that exported to developed countries, its production technology and quality standards is also in line with international standards, thus the production process execution shall closely keep in track with the international standards, and they are all derived from the developed countries’ national standards, therefore the food safety management level can be considered as "international standards"; Ranking from China's main export markets, the United States, Japan, the European Union are the top three, this more fully shows that China's export of canned food safety level is equal to that of Europe and the United States, and got the recognition from them.

In fact, there is no need to brag about the safety of the canned food. China's first manned spaceship for astronauts, which canned foodstuff occupies more than half the food supply. Some people will have doubts that those canned foods are specially made for them, it surely will be safe. In fact, according to the requirements of the China Inspection and Quarantine departments, all the factories that can export canned food can also produce canned food for the astronauts to eat in space.

The author: Lin Jieben as Chairman of Lixing Group, Deputy director of the Foods Association, Canned Food Science & Technology working committee, President of Zhangzhou Chamber of Commerce of Canned Food. This article was abstracted from the CANNED FOOD, 2015, Vol.6, original article entitled: " To view canned food industry from the point of food safety".