Foreign body contamination is one of the highest-risk failure modes in food and pharmaceutical manufacturing. Regulatory bodies — FSSAI, FDA, BRC, IFS — all expect a documented foreign body detection strategy, and two technologies dominate that conversation: metal detection and X-ray inspection.
Both catch metallic contaminants, but the overlap mostly ends there. X-ray can also flag glass, stone, bone, dense plastic, and rubber — materials a metal detector simply cannot see. Metal detectors, in exchange, cost less, validate faster, and hold up better on wet or conductive products where X-ray image analysis gets noisy.
How Metal Detection Works
A transmitter coil generates an alternating electromagnetic field; a conductive object passing through disturbs that field in a way receiver coils can measure. TCT's multi-frequency detectors run several frequencies at once, holding sensitivity across ferrous, non-ferrous, and stainless steel contaminants without manual retuning between product changeovers.
- Typical capital cost: ₹3–12 lakh for a conveyorised system
- Detection limits (dry product): Fe ≥ Ø0.5mm, non-Fe ≥ Ø0.8mm, SS316 ≥ Ø1.0mm
- No radiation licensing, shielding, or dosimetry requirements
How X-Ray Inspection Works
A low-energy X-ray beam passes through the product on a conveyor; a line-scan detector reads the attenuation pattern, and image-processing software flags anomalies by density rather than conductivity. That's what lets X-ray see glass, bone, and dense plastic — and simultaneously check fill level and component count on the same pass.
- Typical capital cost: ₹15–50 lakh+, plus radiation compliance overhead
- Detects glass ≥2mm, calcified bone ≥3mm, dense plastic ≥4mm, alongside all metals
- Unaffected by metallic or aluminised packaging, unlike metal detection
The Decision Framework
In practice the choice comes down to five questions: what contaminants sit in your HACCP risk register, whether your packaging is metallic or aluminised, whether your product is wet or conductive, whether your retail customers mandate X-ray in their supplier code, and what your capex budget and ROI timeline actually allow. Metal detection remains the right call for most pharmaceutical solid-dosage lines; X-ray becomes mandatory the moment glass, bone, stone, or dense non-metal contaminants enter the risk profile, or metallic packaging rules out reliable metal detection.
Key Takeaways
- Start from your HACCP risk register, not the technology catalogue — the contaminants you've identified should drive the technology choice.
- Metal detection is still the right fit for the majority of pharmaceutical solid-dosage lines, with simpler validation and no radiation compliance burden.
- X-ray becomes necessary once glass, bone, stone, or metallic packaging enter the picture.
- Check your retail customer codes before specifying — a supplier mandate can override your internal risk assessment.
- A combined metal detector + check weigher system often delivers the coverage most food retailer codes ask for, at a lower cost than standalone X-ray.
Still unsure which system is right for your line? TCT's application engineers offer free 30-minute consultations to review your HACCP register, product specifications, and compliance requirements.