Özlük, GKrausová, G2026-03-312026-03-3120251212-18001805-9317http://dx.doi.org/10.17221/36/2025-CJFShttps://hdl.handle.net/11491/9620The resilience of lactic acid bacteria (LAB) in commercial probiotic products remains a critical area of investigation, particularly regarding their capacity to survive the harsh gastric environment. Scientific guidelines indicate that at least 6 log CFU center dot g-1 of viable probiotics must reach the intestines to achieve therapeutic benefits, which often requires an initial concentration of 8-9 log CFU center dot g-1 in the product. However, national regulations may specify lower thresholds; for example, Turkish Food Legislation requires 6 log CFU center dot g-1 for probiotic products and 7 log CFU center dot g-1 for kefir products. This study evaluates the in vitro gastric survival of LAB in 20 probiotic-labelled foods and 5 supplements available in the Turkish market using a simulated gastric model. Results reveal that 75% of the marketed probiotic-labelled foods comply with their label claims. Additionally, 55% of the samples demonstrate LAB strains fully resistant to gastric acidity. Dairy-based products exhibit significantly better survival rates under simulated gastric conditions compared to supplements, highlighting their potential for enhanced therapeutic efficacy.enprobioticsgastrointestinal conditionslegislationviabilityArticle43510.17221/36/2025-CJFSWOS:001586657100001