Continuous thermal treatment of pumpable products

Initially established in the dairy industry, continuous processing technologies have gradually spread to other sectors such as juices, soups and ready meals.

For these manufacturers, continuous heat treatment technologies are of considerable interest, as they enable significant gains to be made in terms of productivity and energy consumption, as well as in the quality of processed products (organoleptic and nutritional quality).

Continuous heat treatment, in particular by direct heating, makes it possible to limit the cooking value while ensuring product safety thanks to an appropriate sterilizing value.

These technologies, on the other hand, can only be used on pumpable products, i.e. either homogeneous liquid products, or products with lumps distributed regularly in a sufficiently buoyant phase.

These systems are particularly interesting for large production runs of the same product (due to equipment dead volumes and cleaning times), even though small-scale systems do exist, these are reserved for pilot use. Although economically more costly than discontinuous technologies, their productivity makes them profitable for large production runs.

Like all heat treatment technologies, this technology requires a high level of expertise on the part of manufacturers, particularly during the conditioning phase to avoid any post-heat treatment re-contamination.

The aim of this article is to present the state of the art in continuous heat treatment technologies. It presents the range of existing technologies, the scale validation method applied to continuous treatment and the critical points surrounding the use of these technologies.

A glossary and table of symbols are provided at the end of the article.