Nonnutritive Sweeteners in Breast Milk.

Nonnutritive sweeteners (NNS), including saccharin, sucralose, aspartame, and acesulfame-potassium, are commonly consumed in the general population, and all except for saccharin are considered safe for use during pregnancy and lactation. Sucralose (Splenda) currently holds the majority of the NNS market share and is often combined with acesulfame-potassium in a wide variety of foods and beverages. To date, saccharin is the only NNS reported to be found in human breast milk after maternal consumption, while there is no apparent information on the other NNS. Breast milk samples were collected from 20 lactating volunteers, irrespective of their habitual NNS intake. Saccharin, sucralose, and acesulfame-potassium were present in 65% of participants' milk samples, whereas aspartame was not detected. These data indicate that NNS are frequently ingested by nursing infants, and thus prospective clinical studies are necessary to determine whether early NNS exposure via breast milk may have clinical implications.

Clonal Clustering Using 10-Gene Multilocus Sequence Typing Reveals an Association Between Genotype and Listeria monocytogenes Maximum Growth Rate in Defined Medium.

We used a 10-gene (10G) multilocus sequence typing scheme to investigate the diversity and phylogenetic distribution of 124 Listeria monocytogenes strains across major lineages, major serotypes, and seven epidemic clones that have been previously associated with outbreaks. The 124 isolates proved to be diverse, with a total of 81 sequence types (10G-STs) belonging to 13 clonal complexes (CCs), where all STs of the same CC differ from one another in up to 3 of the 10 alleles (named as 10G-triple-locus-variant-clonal-complexes [10G-TLV-CCs]). Phenotypic characterization for 105 of the 124 strains showed that L. monocytogenes had variable maximum growth rate (µ(max)) in a defined medium at 16°C, and classification by lineage or serotype was not able to reflect the genetic basis for the difference of this phenotype. Among the six major 10G-TLV-CCs, 10G-TLV-CC4 that included lineage I strains had significantly lower µ(max) (Tukey honestly significant difference adjusted [adj.] p < 0.05) compared to 10G-TLV-CC1 and 10G-TLV-CC3 that both comprised lineage II strains, indicating a distinct difference in growth of these L. monocytogenes isolates under nutrient-limited conditions among some of the CCs. However, the other three (10G-TLV-CC2, 6, and 10) of the six major 10G-TLV-CCs containing either lineage I or lineage II strains did not show significantly different µ(max) compared to the others (adj. p < 0.05). Our findings highlighted the importance of using molecular typing methods that can be used in evolutionary analyses as a framework for further understanding the phenotypic characteristics of subgroups of L. monocytogenes.