Pate is a homogeneous finely ground minced meat, vegetables, mushrooms or other ingredients. This product is quite popular in the daily diet of each of us, as it is tasty, nutritious and healthy. Moreover, the variety of possible ingredients allows you to create the most interesting recipes.
In this article, we will discuss the group of sterilised pates that are most often seen on the shelves of Ukrainian supermarkets. Sterilised products are very popular primarily because of their long shelf life. An alternative option is chilled products, which should be stored in a refrigerator at +4 - +6C. To begin with, let's understand what sterilisation is and why it is needed.
The term "sterilisation" refers to the process of heat treatment to destroy harmful microflora such as microorganisms, bacteria, fungi, etc. We all know how long fresh or even cooked meat can be stored - a maximum of 3-4 days. Sterilised canned meat has a shelf life of several years.
Freshly made pate is not only a delicious addition to buttered toast, but also a potential home for harmful microorganisms. After a certain period of time has elapsed since its preparation, our food becomes unfit for consumption, and even dangerous to human health. The solution that prevents product spoilage is heat treatment, i.e. sterilisation.
During sterilisation, the product is kept in a hermetically sealed container. For example, pates can be seen in a tin can, glass or laminate tray. Being in a closed container, after sterilisation, the product remains isolated and inaccessible to foreign microflora.
Heat treatment modes are selected based on the characteristics and properties of the product. In particular, the main factors are the ratio of water to solids, acidity and sugar level. The size of the container in which the product is stored should be noted separately. The temperature must penetrate each layer of the product, and the thicker the layer, the more difficult it is. For example, two identical jars of pate and water will require different amounts of heat to heat, as the thermal conductivity depends on the different viscosities. The more viscous and dense the product, the more difficult it is for the molecules to move and transfer heat energy.
The sterility of a canned product can be achieved by maintaining it at a temperature above 100 °C for a certain period of time. The sterilisation cycle is always defined in terms of a temperature/time pair. Exposing the product to temperatures above 100 °C for a certain time leads to the accumulation of a sterilising value, called the Fo value (F zero). The appropriate time/temperature or Fo value required for a given product depends on the population (number), nature of the microorganisms or degree of contamination. The higher the number, the higher the Fo value and vice versa. To determine the sterilisation cycles, each new product is subjected to heat penetration tests. These tests help to determine at which combination of time and temperature the required Fo value is achieved to ensure sterility. This suitable amount can be achieved either by a high temperature and a short time or by a lower temperature and a longer time. With any combination of time and temperature, the desired result can be achieved. However, the quality of the products after sterilisation may vary depending on the combination chosen. The following are examples of temperature and time combinations for a Fo number of 10:
- 41 min. at 115°C
- 10 min. at 121°C
- 3.2 min. at 126°C
- 1.3 min. at 130°C
On an industrial scale, sterilisation is carried out in a machine called an autoclave in production facilities. An autoclave is usually a cylindrical (horizontal or vertical) pressure vessel. The already packaged product is loaded into it and heated. There are various heating technologies - full immersion in water, hot steam treatment, spray. However, one of the most versatile and progressive solutions is the "water cascade" technology developed by the French company Steriflow back in the 70s of the last century. For more than 40 years, Steriflow solutions have been associated with reliability and energy efficiency.
Looking at the whole, there is nothing supernatural about the Steriflow design: the autoclave consists of a cylindrical vessel, a pump, a valve comb, a control panel and a plate heat exchanger. Modern engineering knows of much more complex designs. But the expression "everything ingenious is simple" is appropriate here. Moreover, the highlight of Sterilfow's creation is the all-welded Platular plate heat exchanger. The fact is that Steriflow is part of the Barriquand group of companies, global specialists in non-standard heat exchange equipment. First of all, it is worth mentioning that the heat exchanger defines the principle of the water cascade. Inside the autoclave, a constant volume of water circulates through the heat exchanger and irrigates the product inside the vessel. During heating, the outer circuit of the heat exchanger is supplied with hot steam, and during cooling, with cold water. The challenge was to develop a heat exchanger that was as adapted as possible to the production sterilisation regimes. The critical point is resistance to thermal expansion of the metal, which occurs when switching from steam to cold water abruptly. The throughput capacity is also not the least important. The Platular is a solution to all these issues.
In the production of canned pates, 2 things are important: the quality of sterilisation of the final product and energy efficiency. With the Steriflow autoclave in your arsenal, you get: the gentlest and most efficient heat penetration into the product. As a result, the sterilisation cycle is shorter and the product does not burn. - uniform temperature distribution, resulting in the same quality of the entire batch at the end of the cycle. - low energy consumption, namely steam and water.
A heat exchanger allows the warm condensate and water to be recirculated. Independent backpressure control and water irrigation allow the processing of products in all possible types of packaging, soft or rigid.
All of the above makes the Steriflow autoclave the ideal sterilisation tool and the perfect solution for sterilising pates.
The topic of autoclaves is quite in-depth, and if you have any questions, you can talk to the specialists of Steiner-Ukraine, the exclusive representative of Steriflow in Ukraine, for more information.