Mass balance, in relationship to food production, can be defined as being the ability to account for all quantities of raw materials, waste, work-in-progress and finished product. Correct calculations ensure that, in the event of a recall, you can account for all potentially affected raw materials and finished product. In this post, find out the key elements that you need to consider when undertaking and documenting mass balance.
Traceability Relationship
Mass balance has a direct relationship with traceability. So, in saying this, you need first to have a clear understanding of how the product is traced through your food production system. Start with inputs and finish with outputs. I find it helpful to draw a map of the process flow.
Weight Management is key
Mass balance is all about quantity in the form of weights and measures. You need to know the weights of:
- Ingoing raw materials or inputs
- Process gains or losses
- Waste
- Rework
- Production / Quality Testing Samples
- Finished product
- Customer Returns
If you don’t specifically know the weights of each element listed above, trials may need to be established to collect this information. A food business that has a good grasp on their production processes and costs will be better positioned to achieve a total and equal mass balance.
Consider packaging
Many of the current GFSI recognised standards require packaging and labels to be part of any mass balance calculation. These are commonly overlooked area for many food manufacturers. Ensure that you consider direct contact packaging, shippers, security ties and adhesive food labels.
Mass Balance Records
Like many of your other food compliance requirements, you need to be able to evidence that your food business can successfully achieve mass balance. Records need to be maintained to clearly show the weights (loss and gain) of each considered element at different process steps.
It is helpful to visualise at what step in the process you need to record mass information. Do this by documenting the inputs and outputs to each of your flow process steps. Here is a straightforward example using four subsequent process steps.
Using the case in the image above, you would need to record:
- The ingoing raw material weights and the total weight (sum) at the “Ingredient Weigh-up” step.
- The weight of the waste at the “Cut dough pieces’ step.
- The final weight of the baked bread
With this core information captured, you can then easily calculate the mass balance.
Variation Warnings
Due to the nature of food manufacturing, there will always be variations in weights and measurements. Record the exact weights at each relevant process step and avoid estimates or assumptions. Here are some common sources of variation to watch for:
- Raw Material Packaging: The stated weight on packaging (e.g., 1 kg) may not match the actual content weight due to fill tolerances or settling during transport
- Processing Variables: Factors like moisture loss, temperature changes, and equipment calibration can affect weight measurements
- Measurement Tools: Scale accuracy and calibration status can impact recorded weights
To manage these variations effectively:
- Use calibrated scales and measuring equipment
- Document actual weights rather than nominal or labeled weights
- Establish acceptable variance thresholds for each process step
- Investigate and document any variations outside of established parameters
Test your system
Regular testing of your mass balance system is crucial for maintaining accuracy and reliability. Here’s how to implement an effective testing program:
- Frequency: Conduct mass balance tests at least annually, or more frequently for high-risk products
- Integration with Mock Recalls: Include mass balance verification as part of your mock product recall exercises to simulate real-world scenarios
- Product Coverage: Test across your full product range, as different products may have unique challenges:
- Complex products with multiple ingredients
- Products with high wastage rates
- Products with significant processing steps
Document all test results, including any discrepancies found and corrective actions taken. This documentation will prove valuable during audits and help identify trends or areas for improvement in your mass balance system.
Final Thoughts
Mass balance is a critical component of any food safety and compliance program. When implemented correctly, it provides transparency, accountability, and confidence in your production processes. Not only does it support traceability and recall requirements, but it can also help identify process inefficiencies and potential cost savings opportunities.
Remember that achieving accurate mass balance requires dedication to detail, proper record-keeping, and regular system testing. By maintaining robust mass balance procedures, your food business will be better equipped to handle regulatory requirements, maintain customer confidence, and respond effectively to any food safety incidents.
