Furthermore, an optimum MW of 1.5 kDa was found [41]; and the most effective MW against S. aureus and E. coli was reported to be 470 kDa, when the testing range was 1-1,671 kDa, knowing that, in both cases, the MICs were ca. 0.08% (w/v) [22]. The aforementioned differences are probably accounted for by the distinct experimental conditions used by those authors, namely, viz. the MW range, the degree of deacetylation (as already mentioned), the concentration, the final pH (which influences ionization of chitosan), the solvents employed (e.g., acetate buffer, acetic acid, water, and lactic or formic acid), the sources of chitosan, and the origin of the bacteria as aforementioned [39].