21 CFR 117 Subpart B

This glossary term is part of the SG Systems Global regulatory & operations guide library.

Updated January 2026 • FSMA CGMPs, personnel & hygiene, plant & grounds, sanitation, equipment & utensils, processes & controls, warehousing & distribution basics • Primarily Food & Beverage Manufacturing (baseline GMP discipline, audit readiness, prerequisite programs)

21 CFR 117 Subpart B is the Current Good Manufacturing Practice (CGMP) foundation inside FSMA Preventive Controls for Human Food. It defines the baseline facility and process conditions required to reduce the risk of adulteration: personnel hygiene, plant design and maintenance, sanitation, equipment and utensils, process controls, warehousing, and defect/action protections. If Subpart C is the risk-based preventive control “design,” Subpart B is the environment that makes those controls credible.

Subpart B is where many facilities get caught off guard because it looks “basic” until an inspector walks the floor. Most FDA observations tied to Part 117 start with Subpart B conditions: poor allergen segregation, weak sanitation execution, uncontrolled traffic patterns, improper equipment design, poor pest control, inadequate handwashing, condensation dripping onto product zones, or warehouses that allow cross-contact. Subpart B doesn’t require a fancy hazard analysis to cite. It’s the baseline expectation for operating a food facility.

Tell it like it is: if your Subpart B posture is weak, your preventive controls program is performative. You can write a beautiful food safety plan, but you can’t run a reliable system in a plant with uncontrolled hygiene, poor maintenance, and weak segregation. Subpart B is the operational discipline layer that keeps the rest of Part 117 from collapsing.

“Subpart B is what stops your facility from manufacturing hazards faster than your food safety plan can document them.”

1) What people mean when they cite 21 CFR 117 Subpart B

When someone cites Subpart B, they usually mean “the FDA can cite us for the way we run the plant,” regardless of whether we have a written food safety plan. Subpart B is the CGMP floor: the basic requirements that apply broadly, and that are visible during a walkthrough.

In practical terms, Subpart B is what inspectors use to assess whether your plant conditions prevent contamination. It’s also what auditors use to determine whether your hazard controls have a chance of working.

2) Why Subpart B is the foundation of FSMA preventive controls

Subpart C preventive controls cannot compensate for a chaotic plant. Subpart B provides the stability layer: controlled hygiene, controlled environment, controlled equipment condition, and controlled material handling. These are “prerequisite programs” in HACCP language, and they must be executed consistently.

Subpart B failures create hazards directly:

• poor sanitation increases microbial risk,
• poor segregation increases allergen cross-contact risk,
• poor maintenance increases physical contamination and process instability,
• poor warehouse discipline increases mislabeling and identity loss.

So Subpart B is not “basic compliance.” It is the operational baseline that makes hazard analysis and preventive controls credible.

3) Scope map: which operations Subpart B touches

Subpart B touches almost everything inside a food facility. A practical scope map:

Because Subpart B is broad, the best way to manage it is through structured prerequisite programs with clear accountability and evidence.

4) Personnel and hygiene: where most “basic” failures happen

Personnel hygiene is where “simple” failures become high-consequence. Subpart B expects controls such as:

• Health and illness reporting: preventing sick workers from contaminating food.
• Handwashing discipline: availability and use of handwashing stations.
• Protective clothing: using appropriate PPE (see PPE).
• Hygienic behavior rules: no eating, drinking, jewelry, and similar contamination controls in production zones.
• Training and supervision: ensuring workers know and follow hygiene practices.

These controls fail when they’re treated as signs on the wall rather than enforced behaviors with supervision and accountability. Inspectors can detect this immediately by observing the floor.

5) Plant and grounds: facilities, traffic, and environmental control

Plant conditions drive contamination risk. Subpart B expects facilities to be designed and maintained to prevent contamination. Practically, this includes:

• Water control: avoiding standing water, ensuring proper drainage.
• Condensation control: preventing dripping onto exposed product or food-contact surfaces.
• Traffic control: controlling people and forklifts between raw and RTE zones to reduce cross-contamination.
• Pest prevention: keeping grounds and building conditions from creating harborage.
• Waste management: preventing waste from becoming a contamination source.

These are not “facility niceties.” They are hazard drivers. If your plant creates water and residue harborage, your sanitation program will always be reactive.

6) Sanitary operations: cleaning, sanitation, and verification discipline

Subpart B expects sanitary operations to prevent contamination. The operational discipline is: clean when required, clean correctly, and verify when needed.

Key components include:

• sanitation schedules and responsibilities,
• chemical control (correct chemicals, correct concentrations, correct storage),
• pre-op inspections (cleanliness before start-up),
• verification methods (see cleaning verification),
• validation where required (see cleaning validation),
• environmental monitoring where applicable (see EM).

Sanitation fails when it’s treated as “done” because someone signed a checklist. Subpart B pushes you to treat sanitation as a control system with evidence.

7) Equipment and utensils: hygienic design and maintenance reality

Equipment is a contamination amplifier when it’s poorly designed or poorly maintained. Subpart B expects equipment and utensils to be:

• Cleanable: designed to avoid harborage points and allow effective cleaning.
• Properly maintained: preventing flaking paint, rust, lubricants, and physical hazards.
• Suitable materials: food-contact surfaces appropriate and intact.
• Protected from contamination: stored and handled so cleaned tools remain clean.

Inspectors frequently cite plants for equipment condition because it’s a direct food safety risk and visible evidence of weak control culture.

8) Processes and controls: GMP discipline on the shop floor

Subpart B also covers how you handle food during manufacturing. This includes controls such as:

• preventing contamination during processing,
• handling of rework and reprocessing under control,
• protecting food-contact surfaces,
• foreign material prevention and detection (see foreign material inspection),
• managing containers and utensils to prevent mix-ups and contamination.

Subpart B is the “execution hygiene” of production. It’s what keeps process from adding risk while you’re trying to control risk.

9) Allergen and cross-contact controls inside CGMPs

Even before you reach Subpart C preventive controls, Subpart B CGMPs include allergen and cross-contact-relevant practices. Practical expectations include:

• segregation of allergenic ingredients (see allergen segregation),
• preventing allergen cross-contact (see cross-contact),
• cleaning practices that remove allergen residues,
• label control practices that prevent mislabeling.

The practical point: allergen programs often fail at the interface between warehouse, production, and packaging. Subpart B expectations push you to control those interfaces even before you build formal allergen preventive controls in Subpart C.

10) Warehousing and distribution: storage, segregation, and protection

Subpart B includes storage and handling expectations because hazards don’t stop when product leaves the processing line. Warehouse controls include:

• Protection from contamination: prevent product exposure, protect packaging integrity.
• Segregation: keep allergens, chemicals, and incompatible materials separated.
• Temperature control: protect shelf-life and food safety where required.
• Inventory hygiene: prevent pest and environmental contamination in storage.
• Receiving discipline: basic inbound checks (see incoming inspection) and appropriate quarantine/hold behaviors.

Warehouse discipline is often the hidden weak point in Subpart B audits because many facilities focus on the production room and ignore the storage reality.

11) Defect action levels and product protection

Subpart B also expects facilities to protect food from adulteration, including controlling defects and preventing contamination sources. Operationally, this is where foreign material control, product protection, and monitoring for defects become part of the CGMP program.

Practically, this includes:

• foreign material detection and verification (metal detectors, X-ray, sieves),
• glass and brittle plastic programs,
• product protection during storage and processing,
• controlled disposition when defects are found (hold/release discipline).

These controls are often tied to customer requirements and GFSI expectations as well.

12) Prerequisite programs: making Subpart B executable

Most facilities implement Subpart B through structured prerequisite programs (PRPs). Common PRPs include:

• sanitation program (SSOPs),
• pest control program,
• glass and brittle plastic program,
• allergen management program,
• preventive maintenance program,
• employee hygiene and training program,
• chemical control program,
• warehouse and storage controls.

PRPs fail when they exist as binders without daily execution evidence. Subpart B is not satisfied by having programs; it’s satisfied by executing them consistently.

13) Inspection posture: what inspectors pressure-test first

Inspectors often start with what they can see. Subpart B items are visible and immediate. Common pressure-test targets:

• handwashing stations and hygiene behavior,
• sanitation condition of equipment and hard-to-clean areas,
• condensation and drainage issues,
• pest evidence and harborage conditions,
• allergen segregation and changeover practices,
• warehouse storage and protection from contamination.

Subpart B issues can cascade: once an inspector sees fundamental control weaknesses, they expand scope into Subpart C and Subpart F record integrity quickly.

14) Copy/paste readiness scorecard

Use this as a blunt internal test. If you can’t answer cleanly, fix operations—not the wording.

15) Failure patterns: how Subpart B gets “done” without control

• GMP theater. Signs and training exist, but floor behavior is inconsistent.
• Sanitation as paperwork. Cleaning logs exist without verification; pre-op failures are normalized.
• Deferred maintenance. Condensation, leaks, and harborage issues persist without corrective plan.
• Warehouse blind spot. Storage areas are treated as “not production,” so segregation and protection slip.
• Allergen complacency. Rework and changeovers are handled informally under schedule pressure.
• Tool control gaps. Clean tools are stored in dirty areas; utensils travel between zones uncontrolled.
• Inspection surprise. The system works only when people expect an audit.

Subpart B compliance is not achieved by documentation. It’s achieved by controlled habits, maintained environments, and consistent execution.

16) How this maps to V5 by SG Systems Global

V5 supports Subpart B outcomes by making CGMP execution visible and enforceable where it matters: sanitation status, allergen segregation, warehouse movement discipline, and inspection readiness. In practice, V5 can:

• capture sanitation and verification events as structured records with traceability linkages,
• enforce segregation rules and movement exceptions for allergens and incompatible materials,
• use hold/release gating so nonconforming or suspect product can’t move forward,
• provide real-time visibility into lot status and hygiene readiness, and
• support audit-ready evidence retrieval across PRPs.

For an integrated view, start with V5 Solution Overview. Where Subpart B execution intersects with shop-floor activity, V5 MES captures the events and checks, while V5 WMS enforces storage and movement discipline, and V5 QMS governs holds, deviations, and corrective actions.

17) Extended FAQ

Q1. Is Subpart B just “GMPs”?
Yes, but those GMPs are the baseline for FSMA. They are enforceable requirements that inspectors can cite directly based on plant conditions and practices.

Q2. What’s the fastest way to get cited under Subpart B?
Visible hygiene and sanitation failures: poor handwashing discipline, poor segregation, condensation dripping, dirty equipment, and uncontrolled warehouse conditions.

Q3. How does Subpart B relate to Subpart C preventive controls?
Subpart B provides the environment that makes preventive controls credible. Weak Subpart B conditions will undermine your preventive control system and increase inspection scope.

Q4. Do we need lots of records for Subpart B?
Subpart B is primarily practice and conditions. But many facilities document PRPs (sanitation, pest control, allergen management) to prove consistent execution, especially because those programs also support Subpart C and Subpart F evidence.

Q5. How do we test Subpart B readiness?
Walk your facility like an inspector: hygiene behaviors, sanitation condition, maintenance issues, segregation, warehouse discipline, and evidence of PRP execution. If you only look good during audits, you’re not controlled.

Related Reading (keep it practical)
If you’re strengthening Subpart B, focus first on sanitation verification (cleaning verification) and allergen discipline (segregation and cross-contact), then harden warehouse movement and status controls (quarantine/hold discipline). For the primary regulation text, use 21 CFR Part 117 (eCFR) and the section-level view at 21 CFR Part 117 (Cornell).