A comprehensive battery of tests is used to evaluate honey across key parameters:
authenticity, quality, and safety. Authenticity tests detect adulteration with cheaper sugar syrups, while quality and safety tests check for freshness, proper processing, and contaminants.
Authenticity testing
Authenticity verifies that the honey’s origin is accurately labeled and that it contains no foreign sugar syrups or other additives.
- Stable Carbon Isotope Ratio Analysis (SCIRA): This method detects foreign sugars from C4 plants, such as corn and cane. It compares the carbon isotope ratios (13C/12Cto the 13th power C / to the 12th power C13C/12C) of the honey’s protein and sugar fractions.
- Nuclear Magnetic Resonance (NMR) Spectroscopy: This is considered a gold-standard method that provides a chemical fingerprint of the honey. It can detect both known and unknown adulterants and is used to verify botanical and geographical origins.
- Pollen Analysis (Melissopalynology): Microscopic analysis of the pollen grains in honey reveals the floral sources from which bees collected nectar. It is used to confirm the honey’s declared botanical and geographical origin.
- Liquid Chromatography–High-Resolution Mass Spectrometry (LC-HRMS): This technique identifies artificial sugar syrups, including complex, custom-made ones, which are difficult to detect with other methods.
Quality testing
Quality parameters determine the honey’s freshness, processing history, and overall integrity.
- Moisture Content: The water content, measured with a refractometer, is critical for stability. High moisture levels (above 20% in standard honey) can cause fermentation.
- Fructose and Glucose (Sugar Profile): Honey is primarily composed of these two simple sugars. Testing ensures they fall within the normal range and that the fructose-to-glucose ratio is correct, as adulteration with sugar syrups changes this profile.
- Sucrose Content: Pure, mature honey should have very little sucrose, as bees break it down into fructose and glucose. A high sucrose level indicates that bees were overfed with sugar or that sucrose was directly added.
- Hydroxymethylfurfural (HMF): This compound forms when honey is heated or stored for long periods. Low HMF levels indicate freshness, while high levels suggest overheating or aging.
- Diastase Activity: Diastase is an enzyme added by bees that is sensitive to heat. Testing for its activity measures the honey’s freshness and confirms that it has not been overheated.
- Electrical Conductivity: This test measures the mineral content in honey, which varies by floral source. It can help distinguish nectar honey from honeydew honey and detect adulteration.
- Acidity and pH: The honey’s natural acidity protects it from microbial growth. Abnormal pH or acidity levels can indicate fermentation or spoilage.
- Total Ash Content: Measuring the residue left after burning a sample gives an estimate of its mineral content, which is used to help determine floral origin.
Safety testing
Safety tests ensure that honey is free from harmful substances that can accumulate from the environment or beekeeping practices.
- Antibiotic Residues: Traces of antibiotics, such as streptomycin and tetracyclines, must be monitored, as their use is often prohibited in honey production to prevent antibiotic resistance.
- Heavy Metal Contamination: Testing for heavy metals like lead, arsenic, and mercury ensures that honey is free of contamination from environmental pollution.
- Pesticide Residues: Honey can be tested for traces of pesticides, including neonicotinoids, that bees may encounter while foraging.
- Microbiological Hazards: Laboratory testing is performed to screen for harmful pathogens, such as Clostridium botulinum spores, which pose a risk, especially to infants under 12 months.