Understanding retort processing: A review

Abstract

Retort processing is a food preservation technique to address the challenge posed by Clostridium botulinum for commercial sterility of a food product to get microbiologically safe and stable products by heating. This review aims to explore the journey of retort processing, starting from its early use in single‐batch canned foods and progressing to its contemporary applications with different types of containers and heating mediums. Additionally, it will delve into the adaptability of retort equipment, including its ability to operate in stationary and various agitation states, as well as its flexibility in processing speed for both single‐batch and continuous operations.

Microwave-based sustainable in-container thermal pasteurization and sterilization technologies for foods

“…The batch retorts are manufactured in two different configurations: (i) static and (ii) agitating retorts. 3,14 Saturated steam, a steam and air mixture, and hot water under high pressure are used as the heating media. 1,3,15 The static retorts are usually arranged either vertically or horizontally.…”

“…17 The steam venting removes air from the retort vessel and enhances the rate of heat transfer from the heating medium to food containers. 14 At the end of heating, the containers are held at operating temperature to achieve targeted lethality. 1 Then steam is turned off, and a mixture of cooling water and air is introduced into the retort to cool the containers.…”

“…Each shell contains spiral assembly on the surface of the reel to guide the continuous movement of cans through heating and cooling processes. 14,16 As the shell/reel turns, the cans follow the path of the spiral through the shell. The cans transferred from the heating shell to the cooling shell through a rotary transfer valve.…”

“…The cans transferred from the heating shell to the cooling shell through a rotary transfer valve. 14 The retorts are also equipped with multiple vent lines for removal of air from the system and uniform distribution of steam. 15 Though not very common, hydrolock and hydrostatic pressure sterilizers are two other continuous systems for manufacturing of shelf-stable foods.…”

“…In food plants, boilers are most commonly used to generate steam, which is then transported through steam pipes to different heating devices. 14 These boilers normally use natural gas, coal, and oil as the main energy source. The energy used to supply steam is one of the biggest contributors to the costs in food and beverage manufacture operations.…”