Hygienic Design of Closed Equipment for the Processing of Liquid Food

F. Moerman

Catholic University of Leuven — KU Leuven, Leuven, Belgium


There is a global trend in the food industry toward minimal food processing and preservation. But the general tendency to apply mild processing and preservation techniques often shortens the shelf life of food, may put foods at risk and may compromise consumer health. It forces food manufacturers to pay more attention to hygiene during the manufacturing of food. Poorly designed or maintained closed equipment for the processing of liquid foods may compromise the product’s hygienic condition. Cross-contamination may occur even after applying rigorous cleaning and disinfection practices. Typical contaminants are spoilage microorganisms and pathogens, as well as allergens. Additionally, broken equipment parts may find their way in as foreign body contaminants, while poor installation and lubrication practices may result in food contaminated with lubricants.

Closed equipment used for the processing of liquid food falls into two categories: (1) process equipment that can be cleaned in-place and can be freed from relevant microorganisms without dismantling and (2) process equipment that in addition is sterilizable and impermeable to microorganisms so as to maintain its aseptic status. Examples of closed process equipment (components) are closed vessels (reactors) often provided with insulation and cladding, piping and pipe joints, pumps, valves, measurement devices, etc. Good hygienic design of this equipment is essential to ensure that the required level of food safety is maintained, in compliance with compelling national and international food safety legislation, as well as food safety management systems built on the well-known concepts of Good Manufacturing Practices (GMPs), Hazard Analysis and Critical Control Point (HACCP) and prerequisite food safety and quality programs. On request of their customers, many

Food Protection and Security. DOI: http://dx.doi.org/10.1016/B978-1-78242-251-8.00007-2

© 2017 Elsevier Ltd. All rights reserved.

food manufacturers also need to certify their food processing operations against the SQFI (Safe Quality Food Institute), BRC (British Retail Consortium), FSSC 22000 (Food Safety System Certification 22000) or GFSI (Global Food Safety Initiative) standards and/or certification schemes. Interest in correct equipment design has also grown in the light of rising production costs, one reason being that hygienically designed process equipment is much more sustainable and cost-effective from a long-term perspective. Although sometimes initially more expensive, hygienic design may (1) reduce the risk of costly product recalls, (2) reduce labor costs by minimizing the effort and time needed to clean and disinfect, and (3) allow cost savings in the consumption of water, cleaning agents/disinfectants, as well as the energy required to heat the cleaning/disinfection solutions.

Therefore, this chapter aims to familiarize users of closed equipment for the processing of liquid food with food safety hazards related to the design, construction and application of these systems. Furthermore, process equipment manufacturers are made more aware of state-of-the-art engineering solutions to improve the hygiene friendliness of their process equipment. In Section 7.2, an overview is given of the current legislation and standards dealing with the hygienic design of food processing equipment. Section 7.3 lists the basic hygienic design requirements that food processing equipment must meet to produce microbiologically safe food products. Section 7.4 describes the hygienic and food grade materials that can be used in the manufacturing of food processing equipment, followed by a section that outlines the requirements for the food contact surface finish (Section 7.5). In the next sections, we discuss the hygienic design of closed equipment (components) for the processing of liquid food such as closed vessels and reactors, including agitators (Section 7.6), processing and utility piping, including hoses (Section 7.7), pumps (Section 7.8), valves (Section 7.9), pressure measurement devices (Section 7.10), and temperature measurement devices (Section 7.11).

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