Food Compound Analysis Kit
Purpose
A citizen science toolkit for measuring histamine, salicylates, and oxalates in food — with a particular focus on comparing store-bought vs. homegrown produce, and fresh vs. stored/processed samples.
Motivated by the observation that low-histamine, low-salicylate, and low-oxalate diet lists circulating in patient communities (particularly MCAS) are largely built on inconsistent, undated, methodology-variable measurements — often copied between sources with no primary data behind them. See Low-Histamine Diet Evidence Gap.
The goal is to encourage actual measurement over lore, and to build a community dataset of real food measurements. For the biochemistry of why these compounds matter, see the Mast Cell Education wiki.
Analytes
| Compound | Chemistry | Wavelength | DIY Cost/test |
|---|---|---|---|
| Salicylates | Iron(III) nitrate colorimetry (Trinder) | ~545nm | ~$0.10 |
| Oxalates | Copper + Reactive Blue 4 displacement (IDA) | ~607nm | ~$0.25 |
| Total amines | AuNP aggregation (screening only) | 522→650nm ratio | ~$0.05 |
| Histamine (specific) | Enzyme strip (triage confirmation only) | ~450nm | ~$8 |
Triage Strategy
- Run total amine colorimetry (cheap, non-specific) → screens for all biogenic amines
- If elevated → run histamine enzyme strip for specific quantification
- Run salicylate and oxalate assays from same sample split
All three DIY assays run from a single unified extraction. See Unified Sample Prep.
Key Hardware Insight
All three assays read in the 530–650nm range. The AS7265x 18-channel spectroscopy sensor (SparkFun, ~$65) covers all three wavelengths simultaneously without LED swapping — the core of the Colorimeter Build.
Status
- Identify chemistry for all three analytes
- Develop unified sample prep protocol
- Source all reagents (identified, pricing confirmed)
- Colorimeter design specified (AS7265x + Arduino/ESP32 + 3D printed enclosure)
- Document research basis
- Build colorimeter prototype
- Validate protocol on known-concentration standards
- Validate on reference food samples (fresh tarragon, spinach)
- Write calibration procedure with actual data
- Design and print colorimeter enclosure STL
- Write Arduino firmware
- Set up community data repository
- Draft open-source release
Vault Structure
Protocols
- Unified Sample Prep — single extraction → three assay aliquots
- Salicylate Assay — Trinder reaction, 545nm
- Oxalate Assay — RB4-Cu²⁺ IDA, 607nm
- Total Amine Screen — AuNP aggregation, 522/650nm ratio
- Histamine Strip — enzyme strip, confirmation only
- Data Logging Template — standardized measurement record
Hardware
- Colorimeter Build — AS7265x + Arduino/ESP32 + 3D print
Reagents
- Bill of Materials — full sourcing and cost breakdown
Research
- Low-Histamine Diet Evidence Gap — why this project exists
- Salicylate Colorimetry — Trinder reaction background
- Oxalate Colorimetry — RB4-Cu²⁺ IDA background
- Histamine Testing Methods — methods comparison, AuNP vs enzyme
- AuNP Synthesis — citrate reduction protocol
Distribution
- Open Source and Distribution — open source strategy, kit framing, regulatory positioning