The Key Differences Between Pre-requisite Programs (PRPs) and Standard Operating Procedures (SOPs)

 

Introduction

In industries where product safety, quality, and regulatory compliance are non-negotiable—such as food processing, pharmaceuticals, biotechnology, and healthcare—two cornerstone elements support a reliable and consistent quality management system: Pre-requisite Programs (PRPs) and Standard Operating Procedures (SOPs).

While they may appear similar on the surface, PRPs and SOPs serve distinct roles. One lays the groundwork for hygienic and safe operations (PRPs), while the other provides precise, actionable instructions for executing specific tasks (SOPs). Understanding their differences—and how they work in concert—is essential for managers, auditors, operators, and quality assurance personnel.

1. What is a Pre-requisite Program (PRP)?

Definition:

A Pre-requisite Program (PRP) is a set of basic environmental and operational conditions required to produce safe products. These conditions support the foundation upon which more specific food safety or quality systems (such as HACCP, ISO 22000, GMP, or FSSC 22000) are built.

Purpose of PRPs:

PRPs are primarily preventive. Their role is to create a baseline environment that significantly reduces the likelihood of contamination or product safety hazards before they can occur.

For instance, PRPs ensure that:

• The facility is structurally sound and designed to reduce contamination risks.
• Water used in processing is clean and potable.
• Personnel follow hygienic practices.
• Cleaning and sanitation are routinely and effectively conducted.

Examples of PRPs:

Category	Examples
Personnel Hygiene	Handwashing procedures, protective clothing, training in hygiene practices
Facility Design	Pest-proofing, adequate lighting, drainage systems, proper air ventilation
Sanitation	Cleaning schedules, chemical usage, sanitation verification programs
Pest Control	Pest monitoring, bait station maps, professional exterminator contracts
Water & Air Quality	Regular testing of water supply, air filtration systems
Waste Disposal	Segregated waste containers, scheduled waste collection
Supplier Management	Approved supplier lists, supplier audits, specifications for raw materials

Characteristics of PRPs:

• Broad in scope: They apply to the entire facility or organization.
• Preventive by design: Focused on stopping hazards before they arise.
• Not product-specific: Unlike critical control points, PRPs apply generally to all operations.
• Often regulatory: Usually required by national or international regulations (e.g., FDA, ISO, Codex Alimentarius).

2. What is a Standard Operating Procedure (SOP)?

Definition:

A Standard Operating Procedure (SOP) is a written, detailed instruction that describes how to perform a specific task or operation in a consistent and controlled manner. SOPs are used to train staff, monitor compliance, and ensure uniformity across shifts, teams, or sites.

Purpose of SOPs:

SOPs aim to standardize daily operations and minimize variability. This ensures that tasks are performed correctly, consistently, and safely—every time.

They are also key documentation for:

• Employee training
• Regulatory inspections
• Quality audits
• Corrective action investigations

Examples of SOPs:

Activity	SOP Title Example
Cleaning	"SOP for Cleaning the Stainless Steel Mixer (Equipment ID: MX-01)"
Calibration	"SOP for Calibrating Digital Thermometers Using Ice and Boiling Water Methods"
Receiving Raw Materials	"SOP for Inspection and Storage of Incoming Raw Materials"
Maintenance	"SOP for Preventive Maintenance of Conveyor Belt System"
Sampling	"SOP for Microbiological Sampling of Finished Product"
Recordkeeping	"SOP for Completing Daily Sanitation Log Sheet"

Characteristics of SOPs:

• Narrow in scope: Each SOP targets a single task or operation.
• Step-by-step: Written in a format that allows even new employees to follow it without supervision.
• Linked to PRPs and controls: SOPs are used to implement the requirements established in PRPs and HACCP systems.
• Must be updated: Reflects current practices and regulatory expectations.

3. Key Differences Between PRPs and SOPs

Feature	Pre-requisite Programs (PRPs)	Standard Operating Procedures (SOPs)
Definition	General conditions required for safe operations	Detailed instructions for performing a specific task
Purpose	To create a hygienic and safe operational environment	To standardize execution of specific tasks or processes
Scope	Broad, system-wide	Narrow, task-specific
Focus	Preventive and environmental controls	Operational consistency and procedural control
Examples	Personal hygiene policy, sanitation program, supplier control	Cleaning steps, calibration procedure, storage temperature checks
Who Implements	Typically managed by Quality Assurance or Facility Management	Executed by operational staff, line workers, and supervisors
Regulatory Role	Often mandated by law or standards (e.g., ISO, FDA, Codex)	Required for compliance and documentation of internal processes
Documentation	High-level policies and program plans	Work instructions, logs, checklists

4. How PRPs and SOPs Work Together

Though distinct, PRPs and SOPs function as two sides of the same coin.

Example Scenario:

Let’s consider a PRP on sanitation:

• The PRP might state: “All food contact surfaces must be cleaned and sanitized at the end of each production shift using validated methods to prevent cross-contamination.”

To operationalize this PRP, a company will create SOPs such as:

• SOP-001: Cleaning and Sanitizing the Slicing Machine
• SOP-002: Verification of Sanitation Effectiveness Using ATP Swabs
• SOP-003: Daily Sanitation Checklist and Documentation Procedure

Each SOP provides the "how" to the "what" and "why" established by the PRP. Together, they ensure the organization is not just aware of the risks but is actively mitigating them in a documented and standardized way.

5. Regulatory and Certification Perspectives

Various international standards reinforce the importance of both PRPs and SOPs:

Standard/Framework	Emphasis
HACCP	PRPs are required as a foundation; SOPs are tools to manage CCPs
ISO 22000	Divides PRPs into Operational PRPs and Basic PRPs, alongside SOPs
FDA (FSMA)	Requires written procedures and preventive controls
GMP	Calls for both facility-level controls (PRPs) and operational SOPs

Conclusion

In summary, Pre-requisite Programs (PRPs) and Standard Operating Procedures (SOPs) are both critical elements of any robust quality management or food safety system. While PRPs establish the necessary environmental and infrastructural foundations for safe production, SOPs provide the detailed execution plans that ensure every operation is performed consistently and correctly.

A strong quality system ensures both are not only present but actively maintained, updated, and reviewed. The synergy between PRPs and SOPs is what turns regulatory requirements and quality policies into safe, repeatable, and auditable practices on the ground.