There is a new urgency to understand the fundamentals of hygienic equipment design since we addressed this subject in a column last year.

Compliance deadlines

First, compliance to the new rules on Preventive Controls for Human Food under the Food Safety Modernization Act commenced in September 2016 for large businesses (those with more than 500 full-time employees and more than $1 million in annual human food sales). Compliance will be required in September this year for “small” businesses and in September 2018 for “very small” businesses.

Compliance for businesses subject to the Pasteurized Milk Ordinance was extended until September 2018 to allow time for changes to the PMO safety standards that incorporate the requirements of the Preventive Controls rule. All companies involved in the production of human and animal foods should assess which of the FSMA rules apply to their company. This includes what current practices are being conducted today that are already FSMA compliant and what practices must be put in place to prepare for the upcoming compliance dates.

Sweeping requirements

Requirements under the Preventive Controls rules are sweeping — facilities must establish and implement a written food safety plan that includes an analysis of hazards and risk-based preventive controls. Further, some provisions of the Current Good Manufacturing Practices (CGMPs), such as education and training, are now binding.

Management is required to ensure that all employees who manufacture, process, pack or hold food are qualified to perform their assigned duties. Individuals must receive training in the principles of food hygiene and food safety, including the importance of employee health and hygiene.

All of this underscores the importance of hygienic equipment design training now for virtually everyone involved in your food processing operation.

3-A Sanitary Standards for all

3-A Sanitary Standards are often regarded as uniquely applicable to equipment for milk processing but these standards are widely applicable to virtually all types of food systems, for both human and animal foods.  For functional reasons, equipment may vary in specified materials, surface finish and/or radius size, or may have additional requirements for a specific process. 

“3-A Sanitary Standards for General Requirements,” approved as an American National Standard in 2014, is a valuable compendium of specific criteria for food processing equipment. These baseline criteria address the features of both food product contact and nonproduct contact surfaces which affect cleanability, including materials and surface finishes. Selected criteria of the General Requirements are listed below:

  • Materials. Whether it is a metal, elastomer, or plastic, the requirements are essentially the same. The material must be inert, non-toxic, non-corrosive, non-reactive, non-contaminating, non-porous, non-absorbent, and impervious to moisture. The second criterion is mechanical properties:  durability, smoothness, and free of cracks and crevices.
  • Finish. 304 stainless steel is an example of a material that meets the hygienic requirements for materials. The General Requirements specifies a product contact surface shall have a roughness average of less than 32 Ra (roughness average).  
  • Permanent Joints. Improperly constructed and finished permanent joints can create surfaces that are not cleanable and are harborage areas for food hazards. The General Requirements outline hygienic methods to produce hygienic joints. Crevice-free and bacteria-tight are the key design features for a hygienic joint. 
  • Accessibility. Hygienic equipment must be designed and manufactured such that all surfaces are accessible for cleaning, sanitizing and inspection. 
  • Self-Draining. All surfaces must be free or self-draining.  Horizontal surfaces must be pitched or sloped to prevent pooling or retention of liquid. Typically a 1/8” pitch per linear foot is recommended.
  • Radii. The radius of intersecting planes affect the ease of cleaning. Sharp corners are hard to clean, while large smooth radii are easier and more reliably cleaned. Good hygienic design requires a minimum of a ¼” radius for angles that are less than 135°.

This list of design considerations increases as the sophistication of the equipment increases. Inclusion of spray cleaning devices opens up design consideration for flow patterns, component placement to eliminate the possibility of shadow areas that will not be properly treated.

The attachment of appurtenances, such as valves and sensors and personal access ports, raise more issues that the designer must consider to assure cleanability, as well as the inspectability of the interior product contact surfaces. No matter how efficient a cleaning system is designed, the surfaces have to be inspected periodically. Inspectability and access to the product contact surfaces is a must for assuring continuing cleaning success.