Читать книгу Essentials of Thermal Processing - Gary Tucker S., Gary S. Tucker - Страница 18

Processing (heating) of the sealed cans started off as being an all‐day event. Appert processed most of his products in boiling water. He did experiment with pressure processing, but at that time ‘digesters’ were quite dangerous and it was not the norm. Around 1863, processors used ‘chemical baths’, where high concentrations of calcium chloride enabled ‘water’ to boil at temperatures approaching 121 °C. This allowed for significantly shorter cooking times. By 1870, basic steam retorts were being used to temperatures up to 121 °C, but they were still quite dangerous and hand operated.

In 1950, the first reel and spiral continuous cooker was introduced and was something very innovative. It was the first retort that did not process in batches. It was called the Anderson‐Barngrover Cooker and was taken over by FMC and is currently John Bean Technology (JBT). These enabled cans to be processed much more efficiently at higher speeds, thus reducing production costs.

Around the same time, aseptic filling was started. In 1961, flame sterilization (using direct gas flame heating of rolling cans) was introduced in France, as was the continuous hydrostatic pressure sterilizer. Today, with computers being able to control equipment we have many more options and more precise control. There are combinations of steam and air, raining hot water, and rotation. All of these developments have the objective to optimize temperature distribution and product heating to improve product quality. Modern retorts can process at temperatures up to 145 °C, yielding faster throughput.