Evaluation of Foreign Metal Material Detection Methods for Hide-on and Hide-off Beef Cattle

Foreign material contamination remains a leading source of consumer complaints in the meat industry, especially in the beef sector. Metallic foreign objects may enter carcasses during upstream animal handling or during processing, creating both food safety risks and economic losses. This study evaluated the efficacy of three detection technologies - x-ray, traditional metal detection, and ultrasound - for detecting foreign metal materials embedded at varying depths and muscle tissue states. Samples representing prerigor hide-on, prerigor hide-off, and postrigor hide-off muscles were collected from beef carcasses (n = 3) and prepared for shallow (20-30 mm), intermediate (40-50 mm), and deep (70-80 mm) tissue depths. Ten metal objects differing in composition and size were placed beneath each muscle tissue state at each depth and offered to blinded technicians for detection. Detection outcomes were recorded as binomial responses, and logistic regression revealed a four-way interaction (p < 0.001) among detection method, muscle state, depth, and metal item. X-ray demonstrated superior performance, detecting all items regardless of depth or muscle state (p̂ = 1.000). Metal detection performed well for large objects at shallow depths; however, efficacy decreased as depth increased and metal object size decreased, and it failed to detect the smallest material (lead seven shot) under any condition. Ultrasound demonstrated the poorest overall performance (p̂ = 0.344), particularly with postrigor muscle and thin metal objects such as needles or wire. Collectively, these results indicate that x-rays offer the most reliable method for detecting embedded foreign metal materials in live animals or carcasses. Metal detection may be useful for large, superficial objects, whereas ultrasound is not valuable for this application.