Ultraprocessed foods represent a severe concern to human health due to their direct link with metabolic diseases. Among these foods, mechanically separated meat-based products are of particular interest due to the use of preservatives and the possible presence of antibiotic residues free or bound to animals’ bone fragments. To demonstrate the potential harmfulness of these substances, 28 samples of commercially available würstels of different suppliers, price category, package size, and produced with mechanically separated chicken and turkey meat were randomly collected from the Italian market. The presence of antibiotics was assessed by LC/HRMS; bone fragments were identified using histological, histochemical, and microscopical analyses; the cytotoxic and proinflammatory activity of the würstels and their ingredients was assessed using ELISA. Bone fragments were detected in all samples, while only 9 out of 28 samples were positive for the presence of doxycycline, although at concentrations far from the maximum residue limits, ranging from 0.36 to 2.50 ug/kg. Most of the samples were cytotoxic at a dilution of 1 : 20 while all of the 3 tested exerted a proinflammatory effect, with significant cytokines’ release (IL-1α, IL-1β, IL-6, IL-8, INF-γ, TNF-α, GM-CSF, and MCAF) at 24 and 36 h ( ∗∗∗P < 0.001). Part of the cytokine release was due to the presence of beech- and oak-based smoke flavoring, where a significant release of IL-1β ( ∗∗∗P < 0.001), IL-8 ( ∗∗∗P < 0.001,  ∗∗P < 0.01), INF-γ ( ∗P < 0.05 and  ∗∗P < 0.01), and MCAF ( ∗∗∗P < 0.001) was observed at 12 and/or 24 h. Although the results need further investigation to elucidate the cytotoxic and proinflammatory process, this can be considered one of the first reports shedding light on the possible toxic potential of some substances routinely used in food processing, even at allowed concentrations. Moreover, it provides new insights into the understanding of the link between high consumption of ultraprocessed meat, increased risk of inflammation, and progression of chronic diseases.