11 myths about sterilization of preserves

11 myths about sterilization of preserves

Through this post we debunk false beliefs and myths about sterilization of preserves.

Our objective is to disprove certain statements about the sterilization of gourmet preserves. These beliefs, after being repeated over and over again, have settled in our minds and have become indisputable truths. However, they are not. They are just misconceptions, which have not been contrasted or argued against. Do you want to know about them?

1. In order to eliminate botulism completely, I must heat food at 134ºC for 1 minute.

This is not entirely true. It is not mandatory that the exact degrees Celsius must be 134 or the sterilization time should be carried out during 1 minute. It will depend on the foods that make up a preserve, their pH and the final product we want.

We will explain it in more detail.

In order for a preserve to be safely consumed without any risk, it is mandatory to eradicate Clostridium botulinum. This is an anaerobic bacterium that produces botulinum toxin and causes botulism, a very dangerous disease that can lead to death. To achieve its eradication, it has been determined that it is necessary to subject packaged foods to a heat treatment that allows the elimination of this bacterium in 12 logarithmic units (12D). Such a decrease assumes that there is a one in a trillion chance that a spore will survive in a unit of treated product.

Mitos sobre la esterilización de conservas y platos preparados: erradicación del

To eliminate these 12 logarithmic units (12D) of Clostridium botulinum, the food must be exposed to a temperature of 121.1ºC (250ºF) during 3 minutes. This is a binomial combination of temperature and time that allows us to experiment with, always taking it as a reference point and bearing in mind that the higher the temperature, the shorter the time and vice versa. And without forgetting the foods that make up our preserves, their pH and the result we are looking for. Not necessarily, the magic formula to eliminate Clostridium botulinum from our preserves must be 134ºC for 1 minute, although there is a possibility. To find out, it is essential to carry out various tests until the product meets our expectations.

2. It is not necessary to sterilize preserves with an autoclave in order to market them.

It is a totally false statement. Yes, it is necessary, because in order to be able to sell your handmade preserves to third parties, current health and hygiene regulations require them to be sterilized using automatic and professional equipment. This is the only way to guarantee the total eradication of microorganisms and spores from the food and also to record how and for how long the preserves have been treated.

Food autoclaves are professional sterilizers for preserves that are hermetically sealed equipment and they are used to pasteurize and/or sterilize food packaged in glass, metal or semi-rigid containers by exposing them to high pressure and temperatures below or above 100ºC for a certain period of time.

Through pasteurization, a partial elimination of microorganisms is achieved because the temperature used is below 100ºC. Therefore, it is essential to refrigerate your preserves after performing a heat treatment.

Mitos sobre la esterilización de conservas y platos preparados: productora elaborando conservas con autoclave.

3. If I sell my preserves at a street market, I do not need to sterilize them with an autoclave.

Another big mistake, another false myth about sterilization. As we have already mentioned in the previous point, in order to be able to market your handmade preserves, it is mandatory to sterilize them with an autoclave. It is required for:

We insist on the importance of sterilizing your preserves with an autoclave if you want to sell them. Failure to do so can lead to serious risks such as food poisoning or even cause botulism. This disease affects the nervous system and causes respiratory and muscular paralysis or even death. As we have already explained, it is caused by Clostridium botulinum, a very dangerous pathogen, and the toxins it produces are very resistant to high temperatures.

4. The vacuum seal is the guarantee that the autoclave sterilization has been done correctly.

Yes and No. The vacuum sealing of your preserve prevents the entry of oxygen or any other contaminating agent into the container. And the purpose of sterilization is to eliminate existing microorganisms in the food.

If no air enters the container, aerobic bacteria cannot grow. However, this does not necessarily mean that we have eliminated the anaerobic bacteria that can grow in the absence of oxygen, among which Clostridium botulinum, mentioned above, stands out for its dangerousness.

5. I can sterilize my preserves through dry heat using an oven.

It is not a safe method and we do not recommend it at all. And it is not reliable because the exact oven temperature is difficult to control. As heat is transmitted through dry air, it takes longer to reach the inner part of the preserves. Therefore, it is not possible to ensure that the food has been exposed to the proper temperature for long enough to eliminate all microorganisms. In addition, ovens do not provide rapid cooling once the sterilization process is complete, nor do they have pressure control systems, so the containers may break.

6. It is not necessary to sterilize the containers before adding the food, because they are sterilized together.

This myth about sterilization of preserves is false. If the containers are not new, they must be thoroughly washed and then heat-treated, including the lids, in order to disinfect them.

On the other hand, if the containers are brand new, but have been stored for some time and/or you think they are not completely clean, it is advisable to clean and disinfect them as well. This can be done either by putting them in a pot with hot water, just like the traditional homemade method, or in a more professional and safe way, using a professional dishwasher.

7. Plastic containers cannot be sterilized because they melt when heated.

Mitos sobre la esterilización de conservas y platos preparados: interior de autoclave con pouches.

Another false myth about sterilization of preserves. Most of the plastics used in the food industry are heat-resistant and can be sterilized. An example of this is Polypropylene (PP), which is used to make trays, or Oriented Polypropylene (OPP), which is used to make the film used to heat-seal said semi-rigid trays.

Likewise, TERRA Food-Tech® autoclaves are equipped with a fast cooling system and pressure support, thanks to which we prevent any deformation or breakage of your containers, whether they are made of plastic, glass or metal.

8. If we sterilize preserves with an autoclave, we waste water and electricity.

A big mistake. With an autoclave, pasteurization or sterilization processes are shorter because the set temperatures are reached earlier. In addition, our autoclaves integrate a system to reduce water and electricity consumption.

9. At the end of a cycle, I must let the autoclave to cool down before starting again.

It is not necessary. As we have already mentioned, our autoclaves are equipped with a fast cooling system, which allows the equipment itself to reduce the chamber temperature by means of cold water jets after sterilization. Thus, at the end of the cycle, the preserves can be removed without any problem and a new heat treatment can be started immediately, without having to wait for the sterilization chamber to reach room temperature.

11. Sterilization means heating food to temperatures above 121ºC.

Not only that. This is another one of the great myths about sterilization of preserves.

Sterilization involves the complete elimination of microorganisms. It can also be achieved at temperatures below 121°C.

It is true that, when it comes to differentiating between pasteurization and sterilization, the difference in Celsius degrees used in while processing is always emphasized. However, what really determines one procedure or another is the number of microorganisms and their pathogens that we eradicate and not the temperature to which the food is exposed. There are different factors that intervene in the development of microorganisms, such as the pH of the food.

In pasteurization, the temperature is set below 100ºC and only a part of the microorganisms are eliminated. For this reason, after a heat treatment, the products require refrigeration and have a shorter shelf life. However, as we have already mentioned, sterilization can also be carried out at temperatures below 100ºC, as long as the acidity level of the food allows it. In any case, sterilization eliminates 100% of the microorganisms present in food. Therefore, it is considered that a sterilized product does not require refrigeration and its shelf life can be up to 5 years.

More information about sterilization of preserves

Mitos sobre la esterilización de conservas y platos preparados: autoclave TERRA Food-Tech con envases de conservas gourmet.

We invite you to visit our blog, where you will find a large number of articles that will be useful if you need more information or want to learn more details about the sterilization and pasteurization of preserves and prepared meals.

In addition, on our website you can also discover the success stories of our customers, where they explain why they decided to dedicate themselves to the world of preserves, their experience with our autoclaves and the thermal processes they apply to their products.

However, if you have any questions or need more information, please do not hesitate to contact us. We will be glad to attend you.

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