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The objectives of the current study were first to determine the prevalence of non O₁₅₇:H₇<i>E. coli</i>, especially Shiga toxin-producing <i>Escherichia coli</i> (STEC) in retailed milk and dairy products in Egypt. Second, the antimicrobial resistance profiling and virulence genes of the isolated <i>E. coli</i> strains were screened. Third, evaluation of the inhibitory effects of D-tryptophan against <i>E. coli</i> O₂₆:H₁₁ was further performed. The results revealed that 20% (30/150) of the samples were STEC positive, with 64 isolates harboring some virulent genes, such as <i>Stx1</i>, <i>Stx2</i>, <i>eaeA</i>, and <i>hylA</i>. Serological identification revealed four different pathotypes belonging to EPEC, ETEC, EHEC, and EIEC. Antimicrobial susceptibility testing revealed that 100%, 98.44%, 92.19%, 71.87%, 65.63% and 64.06% of the isolates had a resistance against tetracycline, oxacillin, erythromycin, nalidixic acid, sulphamethoxazol, and ampicillin, respectively. D-tryptophan addition (40 mM) to <i>E. coli</i> O₂₆:H₁₁-inoculated soft cheese and ice cream revealed a significant reduction (<i>p</i> < 0.05) in bacterial growth, especially when accompanied with other food stressors. D-Tryptophan is considered as an effective food preservative and as a promising alternative candidate in the dairy industry.