RESUMEN
The effect of lemon slices, as well as ascorbic and citric acid impregnated paper discs, on the growth of ten non-typhoidal Salmonella, six <I>Citrobacter freundii</I> and four <I>Proteus mirabilis</I> species on Desoxycholate Hydrogen Sulfide Lactose (DHL) agar were examined in comparison to controls without fruit slices or paper discs applied. After 24 h incubation, thick black rings were observed around fruit slices and impregnated discs growing on non-typhoidal <I>Salmonella</I> serovars and not around the other species. We named this the “MY Phenomenon”. We propose that the phenomenon can be used as a rapid, simple and inexpensive screening test that distinguishes non-typhoidal <I>Salmonella</I> species from other enterobacteriaceae in stool samples.