Wysok et al. (2025) measure heavy metal concentrations in 35 samples of natural sheep casings — the intestinal material used as sausage casings — from Polish production facilities and commercial suppliers, using ICP-MS analysis. This is a niche but relevant matrix given the commercial use of sheep casings in processed meat products and the potential for metal accumulation in gastrointestinal tissues.
Key numbers
Lead (Pb): mean 0.077 ± 0.045 mg/kg (77 ± 45 µg/kg, wet weight). This is the highest mean value among the four metals measured.
Arsenic (tAs, total arsenic): mean 0.036 ± 0.029 mg/kg (36 ± 29 µg/kg, wet weight). Note: speciation not performed; these are total arsenic values.
Cadmium (Cd): mean 0.009 ± 0.008 mg/kg (9 ± 8 µg/kg, wet weight).
Mercury (tHg, total mercury): below limit of quantification (LOQ) in all 35 samples.
n = 35 samples from Polish sources.
Methods (brief)
ICP-MS for Pb, tAs, Cd. tHg by cold vapor atomic absorption spectrometry (CV-AAS) or equivalent. Wet weight basis. Samples represent Polish/EU commercial sheep casings. No speciation performed for As (values are tAs, not iAs). Published in MDPI Foods, peer-reviewed, CC BY.
Limitations: Polish/EU production context; casings are consumed indirectly (casing is typically eaten as part of the sausage rather than extracted), so exposure contribution depends on casing mass fraction relative to sausage product. Sample size of 35 is modest.
Implications
Certification: Sheep casings are not a primary HMT&C certification matrix, but they enter the food supply as a component of sausage and processed meat products. The Pb mean of ~77 µg/kg and As mean of ~36 µg/kg (as tAs) are below EU maximum levels for animal intestines (EU Reg. 2023/915 does not set limits for casings specifically), but both are measurable and non-trivial.
Courses: Illustrates metal accumulation in gastrointestinal organ tissues used as food-contact materials. A data point for the “unexpected matrices” discussion in courses on heavy metals across the food supply.
App: Sheep casings would be listed as an ingredient in sausage products; the app would need to account for casing as a minor-fraction ingredient with detectable Pb and As.