**6. Immuno-allergic potential**

In the literature, it is reported that antibacterial drugs like amoxicillin are not considered as important toxics substances, even at high concentrations; however, an frequent use or exposure to this drugs may produce allergic reactions. Currently, the widely prescribed β-lactam antibiotics are among the drugs most frequently eliciting allergic reactions in human popula‐ tions [105–108].

Protein haptenation plays a key role in immunological reactions to amoxicillin. The haptena‐ tion process occurs through the nucleophilic opening of the β-lactam ring by the attack of free amino groups in proteins, particularly modelling molecular studies found that the most reactive residues towards to amoxicillin is the Lysine, favouring the amoxicilloyl-protein adduct formation, which is able to elicit an immune response [109–112].

Clinically, drug allergy is characterized by a spectrum of immune reactions ranging from mild skins rashes to angio-oedema or life-threatening anaphylaxis, meaning a serious and poten‐ tially life-threatening problem, causing injury to tissues throughout the body. Moreover, diagnosis is complicated and requires a careful medical history, laboratory studies and in many cases oral food challenge to confirm a diagnosis. Particularly, some people have hypersensitive immune systems that overreact to these types of drugs, and without immediate medical treatment, allergic reactions may be fatal [113, 114]. Residues of many antibiotics and antibac‐ terial agents, or haptenised macromolecules, for example penicilloylated proteins in meat and other dietary products from food animals and farmed fish might be responsible for hypersen‐ sitivity reactions in human population. Up to 7–10% of the general population in the world has true allergic sensitivity to penicillin and their related compounds due to prior medical treatment. However, in the literature, only a very small number of cases of hypersensitivity reactions related to food containing residues of penicillin have been reported [115–117]. Even though these cases are very rare, they remark the continuing need to control antibiotic residues vigilantly [117].
