Understanding Critical Limits for Food Safety in HACCP Programs

Written by Staff Writer

A Hazard Analysis and Critical Control Points (HACCP) plan maps out how you keep food safe on the journey from receiving through processing, storage and service. Done well, your plan protects customers, supports product quality and helps you meet regulatory requirements.

Think of your HACCP plan as a safe path that food must travel from start to finish. Along that path, you set checkpoints wherever something could go wrong. Those checkpoints are your critical control points (CCPs). At each checkpoint, you take a specific action to confirm the process is working, such as verifying a cook temperature or confirming a cooler stays cold enough.

That is where critical limits matter. You can have a well-written HACCP plan and still ship or serve unsafe food if your team cannot tell, in real time, whether a CCP is effectively controlling the hazard. Critical limits solve that. They define the exact pass or fail boundary at each CCP, so your team knows when the process is in control and when they must stop, hold product and correct the issue.

In this guide, we will explore what a critical limit is in a HACCP program, how critical limits work at critical control points, how to set measurable critical limits, how continuous monitoring fits in and what corrective actions you need to take when a limit is not met.

Critical Control Points and Critical Limits

You will see these terms together for a reason. They work in tandem.

What is a Critical Control Point?

A CCP is a step where you apply control to a significant hazard. Examples include cooking, cooling, metal detection, concentration, acidification or other steps where you can keep a hazard in check.

What Is a Critical Limit?

The FDA defines a critical limit as “A maximum and/or minimum value to which a biological, chemical or physical parameter must be controlled at a CCP to prevent, eliminate or reduce to an acceptable level the occurrence of a food safety hazard.”

In other words, a critical limit is the highest or lowest value you can allow at a critical control point to keep hazards under control. It serves as a measurable boundary that determines whether conditions at each step of the service journey stay within an acceptable range.

If you have a CCP without a critical limit, then you have a control step with no pass or fail standard. That defeats the purpose of having one in the first place.

Why Critical Limits Matter

Food safety hazards can be invisible. You often cannot see pathogens, chemical contaminants or foreign materials until someone gets sick or injured. Critical limits are meant to help you control hazards before they reach the consumer.

They Create a Clear Standard

You cannot rely on visual checks or end-of-day results to confirm compliance. A critical limit gives you a clear boundary that your team can measure against during production.

They Support Proactive Hazard Control

Establishing critical limits encourages proactive management of hazards rather than waiting for a test of the final product. By using critical limits in your HACCP plan, you can catch loss of control during the process, rather than after a product is packaged or served.

They Reduce Risk for Consumers and Businesses

Noncompliance can increase the risk of foodborne illness or injury. It can also harm consumer confidence and your business reputation. Having critical limits in place helps your company meet regulatory requirements and standards for food safety while protecting customers.

Establishing Critical Limits

You should set critical limits based on the results of the hazard analysis you conducted while creating your HACCP plan.

Work in this order:

1. Identify potential hazards in your process, raw materials and finished product.
2. Choose the points where you can best measure and control those hazards.
3. Establish the limits that provide control at each of those points.

Effective critical limits must be able to detect or prevent identified hazards while maintaining product quality and regulatory compliance. They must also be something that can be monitored consistently during normal day-to-day operations.

If your process cannot meet the limit, you change the process. You do not weaken the limit to match current performance.

Regulatory Requirements and Scientific Evidence

Critical limits should be established based on:

• Regulatory requirements and relevant standards.
• Scientific evidence, including published research and industry studies.
• Validated data from your operation.

This matters because you need to be able to explain how and why you selected each limit. Auditors, inspectors and customers will want to know where the number came from and how it controls the hazard.

Each Critical Limit Must Be Measurable or Observable

To be effective, each critical limit must rely on a measurable or observable criterion. Measurable usually means a numeric value. Observable means it meets a clear pass or fail condition within defined characteristics.

Examples of measurable criteria include:

• Temperature
• Time
• pH levels
• Water activity (vapor pressure)
• Concentration
• Detection thresholds

Examples of observable criteria include:

• Visual cleanliness
• Color
• Presence of foreign objects
• Visible mold growth
• Packaging integrity
• Evidence of leaks, spills or residue
• Foam, haze or separation in liquids

Once you have decided on the measurement or observation used to define the critical limit, you must select a specific value. A good rule of thumb is that, if two different people could interpret the same result differently, the criterion is not clear enough.

Examples of Critical Limits

To better understand effective critical limits, let’s look at some real-world examples.

Cooking Poultry

• Hazard controlled: Pathogens such as salmonella
• CCP: Cooking (temperature and time)
• Critical limit: Hold a minimum internal temperature of 165°F (74°C) throughout for 15 seconds.

Controlling Parasites in Fish Served Raw

• Hazard controlled: Parasites in fish intended for raw consumption
• CCP: Freezing (temperature and time)
• Critical limit: Freeze at -4°F (-20°C) for seven days, or -31°F (-35°C) for 15 hours.

Sifting Flour Before Mixing

• Hazard controlled: Physical hazards from foreign objects such as stones, metal or hard plastic
• CCP: Sifting or screening (presence of foreign objects)
• Critical limit: All flour passes through a 20-mesh screen, and screen integrity is verified at start-up and every hour, with 0 tears or gaps allowed.

Cooling Cooked Foods

• Hazard controlled: Pathogen growth and toxin formation
• CCP: Cooling (temperature and time)
• Critical limit: Cool from 135°F to 70°F within 2 hours, then from 70°F to 41°F within four additional hours.

Sanitizer Strength for Dishwashing

• Hazard controlled: Pathogens on food-contact surfaces
• CCP: Sanitizing (sanitizer concentration)
• Critical limit: Sanitizer is mixed within the approved effective range for the chemical or chemicals used, verified with test strips.

Critical Limits vs Operational Limits

Your critical limit is the line that cannot be crossed. Your operational limit is the target that helps your team stay away from that line.

Use operational limits when small variations can push a process close to failure, such as probe placement, product size or line speed. Keep goals realistic and tie them to individual benchmarks like equipment use or procedures so they can be easily monitored.

For example, when cooking ground beef, a minimum internal temperature of 160°F (71°C) is a critical limit, while an operational target of 165°F (74°C) at the coldest spot reduces the chances of sending out a dish with raw meat by accident.

Monitoring Critical Limits

Once you set your targets, you need a monitoring routine that catches problems fast and produces useful records. Monitoring can be continuous, such as an automated sensor with alarms, or routine, such as checks performed at set intervals measured in time or by count. Choose an approach that fits the needs of your process.

Assign Clear Monitoring Tasks

Match monitoring tasks to appropriate actions and tools. Common tasks include:

• Temperature checks. Probe the coldest spot, record the result and include time, product and lot or batch ID.
• Temperature logs. Create manual logs or automate records and review them on a set schedule.
• Thermometer calibration checks. Verify that all instruments used for monitoring remain accurate, then record the check.
• Sanitizer concentration checks. Use chemical test strips at regular intervals, record the concentration and replace solution when required.
• Metal detector checks. Run test pieces at the required frequency and confirm that the devices correctly identify foreign bodies.
• Screen and sieve integrity checks. Confirm that the correct mesh size is used and that no damage is present at start-up and at defined intervals.

Set a Monitoring Check Frequency

Once you know what you are monitoring and how, decide the frequency at which you can perform checks during real shifts.

If the step is high-risk or fast-moving, perform checks often or use continuous monitoring. If the step is low-risk or slow-moving, set longer intervals that still prevent product from moving forward unchecked.

Make Monitoring Straightforward

Monitoring usually fails for simple reasons: The thermometer is across the room, the log is missing key fields or the person on the line is not sure where to measure. You can prevent most of that by making the monitoring process simple and convenient.

Put Tools at the Point of Use

Place monitoring tools where the check happens, not locked in a supply closet:

• Keep probe thermometers, test strips and timers at the workstation for that task.
• Store tools in a labeled holder so staff do not waste time searching.
• Keep sanitizer test strips in a dry, protected spot near the sink or station where solutions are mixed and used.
• Post the failure threshold and the measurement location right next to the tool, so staff do not rely on memory.
• Make spare tools and supplies available so monitoring does not stop when something breaks or runs out.

If tools are easy to find and ready to use, control is easily repeatable across every shift.

Standardize the Steps

Consistency comes from a clear, repeatable method. Make sure to define each variable and step to minimize confusion:

• Describe the measurement location, such as “coldest spot,” including the crucial elements of any of the products and equipment used.
• Designate sampling rules, such as which items to probe, how many per batch and when to recheck.
• Designate what counts as a valid reading, including minimum stabilization time for probes and how to handle thin products.
• Use the same units, rounding rules and terminology across all logs.

By prioritizing consistent steps, monitoring results in reliable data instead of personal judgments.

Use Standardized Fields That Prevent Guesswork

Include fields that answer who, what, when and with what tool the check was made, such as:

• Date and time of sampling
• Product, line and lot or batch ID
• CCP step and measurement location
• Result and units
• Instrument ID
• Operator initials or electronic sign-off

When every entry follows the same format, documentation stays clean, readable and ready for review at any time.

Add Prompts for Early Corrective Action

Operational limits should act like an early warning system. Your team needs to know what to do while there is still time to prevent missing a critical limit.

Add simple prompts that indicate exactly what to do next, such as:

• If the temperature is within 5°F of the critical limit, increase check frequency and adjust the heating or cooling process.
• If sanitizer concentration is low, remix the solution, retest and document the new reading.
• If cooling is falling behind your time target, spread material into shallower containers, improve airflow or switch to an approved rapid-cooling method.

Keep these prompts short and action-based to reduce confusion. Place instructions where staff are likely to look during monitoring, such as on the log, near the tool or in a mobile workflow aid.

Make Monitoring Hard to Skip

Put safeguards in place to prevent missed checks, such as:

• Setting a routine tied to production rhythm, such as at start-up, first product, hourly, changeover and end of run.
• Assigning back-up responsibility for breaks and shift changes.
• Using alarms or reminders for time-based checks, especially during busy periods.
• Reviewing logs during each shift, not days later, so failures are addressed while the affected product is still on site.

If you make it harder to skip a check than to complete it, you protect your process when the pressure rises.

What to Do When a Critical Limit Is Not Met

A missed critical limit is a deviation that must be addressed. Respond immediately and follow a corrective action plan step by step so the team fixes the process and controls any affected product.

1. Control the Product

If monitoring shows a critical limit was not met:

• Stop product from moving forward.
• Identify the affected lot or time window.
• Isolate and hold the product with clear status labeling.

The goal is simple: Keep any possibly affected product identified, held and traceable.

2. Make a Disposition Decision

Once the affected product has been identified, your predetermined plan should address what to do next:

• Reprocess the product if you can restore control safely and remain compliant.
• Discard the product if you cannot confirm safety or if reprocessing is not allowed.

Make sure to document who approved each decision and what happened to the product.

3. Fix The Process

Once the immediate issue is resolved, examine exactly what happened and what can be done to prevent recurrence:

• Adjust equipment settings, line speed, dwell time or cook cycle.
• Replace or repair faulty equipment.
• Retrain staff on measurement techniques.
• Update the monitoring frequency if the current schedule fails to catch deviations.

Corrective action is complete only when you remove the root cause and prevent the same deviation from happening again.

Verify Your System Works and Maintain Records

Monitoring and corrective actions protect food from moment to moment. Verification and recordkeeping prove the system works over time and help you spot patterns before they become problems.

Use verification methods that fit your operation:

• Review logs for completeness, trends and missed checks.
• Review corrective action records to confirm product control and disposition were handled correctly.
• Check calibration records for instruments used for monitoring.
• Observe monitoring on the floor to confirm actual technique matches the written method.
• Confirm alarms, sensors and automated logs function as intended if you use them.

Verification should answer two questions: are you following the plan? And do the results show that limits effectively control hazards?

Maintain Records That Support Food Safety Decisions

Records should be organized and easy to retrieve. Keep detailed records such as:

• Monitoring logs for each CCP
• Corrective action reports
• Verification records, including reviews and observations
• Calibration and maintenance notes for all instruments
• Support documentation that explains how each critical limit was set and validated.

Consistent records help you demonstrate control to auditors and inspectors who may request them as part of their investigation. Recordkeeping also gives you the data you need to improve the process before a deviation happens again.

Support Your HACCP Program with Professional Training

Critical limits turn your HACCP plan into a safety system your team can run, check and defend. When every CCP has a clear minimum or maximum value, you can monitor in real time, spot deviations fast and take corrective action before unsafe product reaches customers.

If you want your team to build a strong HACCP program, State Food Safety’s HACCP Certification course walks through the seven HACCP principles, includes downloadable templates to help you build and implement your plan and is accredited by the International HACCP Alliance.

The coursework is 100% online and designed to match a two-day, 16-hour classroom equivalent. The course includes a final exam and an official certificate you can download right after completion. Sign up today to get certified fast and start building your HACCP plan with confidence!