Food Safety Testing Applications¶
Test Categories¶
| Test | Method | Solarbio Products | Relevant Regulations |
|---|---|---|---|
| Heavy metal detection | Colorimetric kits | Heavy metal assay (BC-series) | GB 2762-2022, EU 1881/2006 |
| Pesticide residue | ELISA-based | Custom residue ELISA | GB 2763-2021, EU 396/2005 |
| Food quality indicators | Enzyme activity kits | Polyphenol oxidase, peroxidase | ISO 3972, GB/T 5009 |
| Nutritional analysis | Spectrophotometric | Protein (BCA), fat, fiber assays | GB 28050, Codex Alimentarius |
| Mycotoxin detection | Competitive ELISA | Aflatoxin B1, ochratoxin A | GB 2761-2017, EU 1881/2006 |
| Antioxidant capacity | Spectrophotometric | T-AOC, DPPH, FRAP assays | AOAC 2012.04 |
| Lipid oxidation | Colorimetric | MDA (BC0025), TBA-RS | GB 5009.181-2016 |
| Enzyme browning | Kinetic assay | Polyphenol oxidase (BC0200) | Industry practice |
Key Assays and Specifications¶
Heavy Metal Detection¶
| Metal | Assay Principle | Detection Limit | Linear Range | Sample Preparation |
|---|---|---|---|---|
| Lead (Pb²⁺) | Colorimetric: dithizone-based | 0.1 mg/L | 0.1–5 mg/L | Acid digestion (HNO₃/HClO₄) |
| Cadmium (Cd²⁺) | Colorimetric: dithizone-based | 0.05 mg/L | 0.05–2 mg/L | Acid digestion |
| Copper (Cu²⁺) | Colorimetric: BCA-based | 0.1 mg/L | 0.1–10 mg/L | Wet ashing |
| Iron (Fe³⁺) | Colorimetric: ferrozine-based | 0.05 mg/L | 0.05–5 mg/L | Acid extraction |
Pesticide Residue ELISA¶
- Sensitivity: LOD 0.01–0.1 ng/mL depending on target pesticide
- Cross-reactivity: Tested against panel of 20–30 structurally related compounds
- Matrix validation: Grains, fruits, vegetables, tea leaves, soil, water
- Extraction: QuEChERS-based (acetonitrile extraction + dispersive SPE cleanup)
- Assay time: 1.5–2 hours (competitive format)
- Recovery: 80–120% for spiked samples at regulatory limits
Mycotoxin Detection¶
| Mycotoxin | ELISA SKU | Detection Range | Sample Types | LOD |
|---|---|---|---|---|
| Aflatoxin B1 | SEKR-0001 | 0.1–25 ppb | Grains, nuts, spices, milk | 0.05 ppb |
| Ochratoxin A | SEKR-0005 | 0.5–50 ppb | Wheat, coffee, wine, beer | 0.2 ppb |
| Deoxynivalenol (Vomitoxin) | SEKR-0010 | 50–2000 ppb | Wheat, corn, barley | 20 ppb |
| Zearalenone | SEKR-0012 | 10–500 ppb | Corn, wheat, soy | 5 ppb |
Sample Preparation Protocols¶
Grain/Nut Extraction (for mycotoxins)¶
| Step | Detail |
|---|---|
| Grinding | Mill to pass through 1 mm sieve |
| Extraction solvent | 70% methanol (v/v) for aflatoxins; water for DON |
| Ratio | 10 mL solvent per 1 g ground sample |
| Agitation | Shake vigorously for 30 min at RT |
| Filtration | Whatman #1 or equivalent filter paper |
| Dilution | Dilute filtrate in sample buffer (1:5 to 1:20 as needed) |
Fruit/Vegetable Extraction (for pesticides)¶
| Step | Detail |
|---|---|
| Weigh | 10 g homogenized sample |
| Add | 10 mL acetonitrile + 1 g NaCl + 4 g MgSO₄ |
| Vortex | 1 min, then centrifuge 5 min at 4000 × g |
| Cleanup | Transfer 1 mL supernatant to d-SPE tube (PSA + C₁₈) |
| Buffering | Transfer cleaned supernatant, dilute 1:10 in ELISA assay buffer |
Quality Indicators¶
| Indicator | Assay | Normal Range in Food | Significance |
|---|---|---|---|
| Peroxide value | T-AOC, MDA | <10 meq/kg (fresh oils) | Rancidity indicator |
| Polyphenol oxidase activity | BC0200 | Varies by fruit/veg | Browning potential |
| Total antioxidant capacity | FRAP/DPPH | Varies by food type | Nutritional quality |
| Protein content | BCA/Bradford | Varies | Nutritional labeling |
| Lipid content | Triglyceride (BC0620) | Varies | Nutritional labeling |