Autoclaves for the food industry

Autoclaves for sterilization processes in the food industry

Within the food processing industry, autoclaves are instrumental in ensuring the sterilization and preservation of food products. This process encompasses the thermal treatment of both canned goods and broadly, any food products necessitating thermal processing at temperatures surpassing 100 degrees Celsius. The goal is always the same: to drastically reduce or altogether eliminate microbial populations within the product.

This process significantly extends the shelf life of canned or packaged food, to the extent that it can last for several years under optimal conditions. This is why most canned foods have such a long shelf life.

The operation of a food autoclave closely mirrors those employed in various other industrial sectors. Nonetheless, within the food industry, its utilization is mandated for the processing of a broad spectrum of food products packaged in glass and metal containers, such as canned seafood, fish, vegetables, fruits, or ready meals.

This requirement is instituted due to the fact that autoclave sterilization of packaged foods ensures the preservation of their contents by guaranteeing the comprehensive eradication of all microorganisms, thereby safeguarding consumer health and expanding substantially the shelf life of the food product.

The operating principle of an autoclave involves the use of steam under pressure. When water is heated and turns into steam, it occupies a much larger volume than in its liquid state. By confining this steam in a sealed environment, such as that of an autoclave, a high pressure is induced. This increase in pressure, coupled with the fact that the steam can reach temperatures significantly higher than 100°C, facilitates an efficient transfer of energy to the material being sterilized, resulting in a rapid increase in the temperature of the load.

Steam generation constitutes an integral component of the sterilization process in autoclaves, achievable through various means such as integrated electric heating elements, an internal steam generator, or an external steam boiler, contingent upon the specific design and model of the autoclave. The process involves heating of water to the point where it becomes saturated steam, distinguished by its improved thermal characteristics that facilitate a quicker heat transfer.

Once the appropriate steam is generated, it completely surrounds the food in its respective containers, ensuring that heat is uniformly transmitted to every corner. The superior effectiveness of moist heat in sterilization processes stems from the steam’s ability to transfer heat more efficiently than dry heat.

Achieving precise control over pressure and temperature is fundamental in the operation of autoclaves, which are outfitted with sensors and valves designed for the real-time monitoring and adjustement of these critical parameters. The increase in pressure directly affects the thermal properties of steam, leading to a rise in its temperature and a consequent reduction in the required exposure time, a crucial factor for the complete inactivation of all microorganisms without compromising the quality of the processed food. It is important to note that the specific settings for the duration and temperature of the sterilization cycle are intricately tailored to the particularities of the food item being sterilized, the size and shape of the container, and the resilience and characteristics of the target microorganisms, to achieve optimal sterilization efficacy.

A critical yet frequently underestimated component of the sterilization process, specially in porous items or wrapped objects, is the elimination of cold air from the chamber prior to sterilization. The presence of air can serve as an insulating barrier, hindering the efficient transfer of heat. Certain models of our autoclaves are capable of performing a prevacuum phase designed to address this issue. During this step, air is evacuated from the chamber before steam introduction, thereby facilitating even and consistent sterilization throughout the load.

Subsequent to the exposure of food to predefined temperature and pressure conditions for a designated duration, it is essential to cool down the food as fast as possible to prevent overcooking and maintain its organoleptic attrbiutes. This rapid cooling process in the autoclave is achieved through a shower water system and a counterpressure system. The interaction between these two mechanisms facilitates efficient cooling of the load while preventing the risk of container breakage.