Root cause analysis: methods and examples

Root cause analysis that prevents recurrence

When a non-conformity appears at a food plant, the immediate reaction is usually to fix the visible problem: withdraw the batch, repeat the process, correct the record. However, without a root cause analysis rigorous, that same problem will come back weeks or months later. Identifying why something happened, not just what happened, is what separates managing quality reactively from building a truly robust system.

What root cause analysis is

Root cause analysis (RCA) is a structured methodology that goes beyond the symptom of a problem to identify its real origin. In the food sector, this approach is essential for meeting the requirements of food safety management systems and for responding properly to internal and external audits.

Its application isn't limited to major failures. Any deviation, however small it may seem, can conceal a systemic weakness: a poorly designed procedure, insufficient training, deteriorated infrastructure, or poor communication between departments. As established by the Regulation (EC) 852/2004 on the hygiene of foodstuffs (Regulation [EC] 852/2004, 2004), food business operators must implement permanent procedures based on HACCP principles, which requires precisely this kind of systematic analysis to ensure control of critical points.

A well-executed root cause analysis produces three outcomes: the immediate correction to contain the problem, the corrective action to eliminate the cause, and the preventive action to stop similar situations from occurring in other processes or areas.

Main methods: the 5 whys and Ishikawa

There are various tools for carrying out a root cause analysis. The most widely used in the food industry, for their practicality and ease of communication, are the 5 whys method and the Ishikawa diagram (or cause-and-effect diagram).

The 5 whys method consists of repeatedly asking “why?” after each answer given until reaching the root cause of the problem. Generally, three to five iterations are enough to move past the symptoms and reach a structural cause. For example:

• Problem: Metal was detected in a batch of canned goods.
• Why? The metal detector didn't trigger the alarm.
• Why? The detector wasn't calibrated correctly.
• Why? The calibration wasn't carried out on the scheduled date.
• Why? There was no alert system to notify the maintenance owner.
• Why? The maintenance plan didn't include automatic reminders.

The root cause isn't the uncalibrated detector, but the lack of a preventive maintenance management system. The corrective action must target that level.

The Ishikawa diagram, also known as the fishbone diagram, is especially useful when a problem has multiple possible causes or involves several departments. It starts from the effect (the problem) and explores the causes grouped into classic categories such as manpower, machinery, materials, method, environment, and measurement. This overall view makes teamwork easier and keeps the analysis from being skewed by a single department's perspective.

Both tools are complementary: the 5 whys help dig deeper into each branch of the Ishikawa diagram, while the diagram ensures that no category of potential causes is overlooked.

How to apply root cause analysis to real non-conformities

The non-conformity analysis is the most common context for applying RCA at a food company. The process follows a logical sequence that should be respected to get solid results.

1. Precise description of the problem. Before analyzing, it's important to clearly define what happened: when, where, in which product, in which process, and how often. A vague description leads to a superficial analysis. Use objective data: records, test results, production reports.

2. Team formation. Root cause analysis shouldn't be the task of a single person. Involving the people who took part in the process brings different perspectives and reduces the risk of organizational causes staying hidden. The quality manager acts as a facilitator, not as the sole judge.

3. Applying the chosen tool. Choose the most suitable method based on the complexity of the problem. For specific, well-defined incidents, the 5 whys are enough. For multifactorial or recurring problems, Ishikawa offers a more complete view.

4. Defining actions. Once the root cause is identified, corrective actions are set with an owner, a due date, and a verification criterion. It's essential to distinguish between the correction (what's done immediately) and the corrective action (what eliminates the cause).

5. Verifying effectiveness. No root cause analysis is complete without checking that the actions have worked. After a reasonable amount of time, it's necessary to review whether the problem has resurfaced and whether the indicators related ones have improved.

How to record the analysis and its closure in Solved

Uno de los principales obstáculos en la gestión de no conformidades es la dispersión de la información: el análisis queda en un correo, la acción en una hoja de cálculo y el cierre en la memoria del responsable. Esto dificulta las auditorías, impide el aprendizaje organizacional y hace imposible detectar patrones de repetición.

With Solved's incidents module, root cause analysis is built directly into the non-conformity management workflow. From the incident record itself, the quality team can document the method used, the causes identified, and the actions defined, assigning an owner and a deadline to each one.

The system tracks the status of each action in real time and generates automatic alerts as the closing deadline approaches. Once all actions are complete, the owner can record the effectiveness verification and formally close the non-conformity, leaving a complete, auditable trace of the whole process.

Solved also makes trend analysis easier: with all non-conformities recorded in a structured way, it's possible to identify which root causes recur most often, which areas concentrate the most incidents, or which suppliers generate the most deviations. This information is extremely valuable for management system reviews and for prioritizing improvement investments.

Managing quality with real data, documented processes, and tools that make the team's work easier isn't just a matter of regulatory compliance: it's a real competitive advantage for any company in the food industry. Root cause analysis, when well integrated into the system, is one of the pillars of that advantage.

References

• Regulation (EC) No 852/2004 of the European Parliament and of the Council of 29 April 2004 on the hygiene of foodstuffs. (2004). https://eur-lex.europa.eu/eli/reg/2004/852/oj?locale=es