When FoodSense and HPLC Disagree: Is the Laboratory Result Always the Gold Standard?
- martinpeacock13
- 6 days ago
- 5 min read
At FoodSense, one of the questions we are occasionally asked is:
"If a FoodSense Generation Four result differs from a laboratory HPLC result, which one should be trusted?"
The instinctive response from many people is to assume that the laboratory result must be correct. After all, HPLC has long been regarded as the industry's reference method for capsaicinoid analysis.
However, the reality is often more complicated, particularly when testing complex manufactured foods rather than simple chilli powders.
This topic builds upon an earlier article discussing variability in SHU measurement:
That article highlighted an important but often overlooked fact: different HPLC laboratories can produce significantly different results when testing exactly the same sample.
In this article, we explore an additional question:
What happens when HPLC is applied to food products that fall outside the scope for which the method was originally validated?
A Real-World Comparison
Recently, FoodSense reviewed a comparison between FoodSense Generation Four measurements and HPLC laboratory results on a range of commercial chilli sauces.
The results were as follows:
Product | FoodSense Gen 4 | Laboratory |
Pomegranate Barbecue Sauce | 7,583 SHU | 5,196 SHU |
Carolina Reaper with Dried Zereshk Sauce | 5,065 SHU | 21,683 SHU |
Scotch Bonnet Chilli Sauce | 52,010 SHU | 29,796 SHU |
Spicy Peanut Butter Sauce | 450 SHU | 783 SHU |
At first glance, two of the products show reasonably good agreement between the two methods:
Pomegranate Barbecue Sauce
Spicy Peanut Butter Sauce
The larger differences occur in:
Carolina Reaper with Dried Zereshk Sauce
Scotch Bonnet Chilli Sauce
The immediate question becomes:
Is FoodSense wrong, or is there another explanation?
Were These Products Within the Scope of AOAC 995.03?
The reported laboratory method was AOAC 995.03.
This is a well-established HPLC method for capsaicinoid determination. However, it is important to understand what the method was originally validated for.
Validated matrices include products such as:
Ground red pepper
Crushed red pepper
Chilli pepper
Ground cayenne pepper
Ground jalapeño pepper
Pepper oleoresins
The sauces listed above are clearly different products.
They contain combinations of:
Fruit solids
Sugars
Acids
Oils
Fats
Proteins
Herbs and spices
Stabilisers and gums
These ingredients can influence:
Extraction efficiency
Sample homogeneity
Capsaicinoid recovery
Analytical repeatability
In other words, these are complex food matrices that sit outside the original validation scope of AOAC 995.03.
This does not mean that the laboratory result is incorrect.
It does mean that the laboratory result should not automatically be assumed to represent an absolute truth without considering the challenges associated with the matrix being tested.
What We Learned from Our Previous HPLC Investigation
This is where our previous article becomes relevant.
In our earlier investigation:
the same chilli powder samples were submitted to multiple independent laboratories.
The resulting SHU values varied substantially:
Laboratory | SHU Result |
Lab A | 34,000 |
Lab B | 50,000 |
Lab C | 23,000 |
Importantly, these were chilli powders, exactly the type of sample for which AOAC 995.03 is intended.
Yet the laboratories did not agree.
The key lesson was simple:
The question is often not "FoodSense versus HPLC" but "HPLC versus HPLC."
If measurable variation can occur between laboratories analysing validated chilli powder samples, it is reasonable to expect even greater uncertainty when testing highly complex sauces.
A Practical Reality Check: What Does the Sauce Actually Taste Like?
Perhaps the most interesting result in the comparison is the Carolina Reaper with Dried Zereshk Sauce.
Method | Result |
FoodSense Generation Four | 5,065 SHU |
Laboratory | 21,683 SHU |
This is not a small disagreement.
The laboratory value is more than four times higher than the FoodSense value.
When differences become this large, there is another useful tool available:
common sense sensory assessment.
A sauce around 5,000 SHU is broadly comparable to the heat range associated with products such as Tabasco® Original Red Sauce.
Most consumers can comfortably taste such a product.
A sauce at approximately 20,000 SHU should deliver a dramatically different sensory experience. It should be significantly hotter and noticeably more aggressive on the palate.
No, tasting is not a substitute for analytical measurement.
However, when one method says a product is approximately 5,000 SHU and another says it exceeds 20,000 SHU, the size of the discrepancy becomes large enough that an organoleptic assessment can act as a useful reality check.
An experienced chilli consumer should be able to determine whether the product behaves more like a mild-to-medium hot sauce in the Tabasco range or whether it exhibits the much stronger heat character associated with the twenty-thousand-SHU range.
For very small differences, taste testing is unlikely to help.
For a four-fold difference, it may provide valuable context.
Looking Beyond the Number
Another important consideration is the evidence available behind a result.
FoodSense Generation Four does not simply provide a SHU prediction.
Users also have access to the underlying Djuli data used to generate that prediction.
This provides visibility into the measurement itself and allows users to review the supporting evidence behind the final result.
By contrast, laboratory customers often receive:
A certificate of analysis
A report
An email
A final SHU value
What they do not always receive is the supporting analytical data, such as:
Raw chromatograms
Peak integration details
Calibration data
Recovery studies
Replicate measurements
Extraction efficiency information
Without access to the underlying analytical evidence, the customer may have little visibility into how the final number was obtained.
This becomes particularly important when large discrepancies occur between measurement methods.
Whenever two methods disagree significantly, an important question is:
What evidence is available to support each result?
Transparency is an essential part of scientific confidence.
Asking Better Questions
Too often, discussions about SHU testing focus on determining which number is "correct."
In reality, the more useful questions may be:
Was the analytical method validated for the product being tested?
What uncertainty exists within the measurement process?
How repeatable is the result?
What supporting evidence is available?
Does the result align with the real-world sensory experience of the product?
These questions encourage a deeper understanding of measurement quality rather than blind acceptance of any individual result.
Conclusion
The comparison discussed here does not prove that FoodSense is right and the laboratory is wrong.
Nor does it prove the opposite.
What it does demonstrate is that measuring capsaicinoids in complex food products is not always straightforward.
The sauces in this comparison fall outside the original validation scope of AOAC 995.03, and previous FoodSense investigations have already shown that different HPLC laboratories can generate substantially different results even when testing validated chilli powder samples.
When analytical methods disagree, the answer is rarely found by looking only at the final SHU number.
Instead, we should examine:
Method suitability
Matrix effects
Laboratory variation
Supporting evidence
Real-world product behaviour
Ultimately, the goal is not simply to obtain a number.
The goal is to obtain a number that genuinely reflects the product being measured.
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