Microbial Contamination of Human Milk Purchased Via the Internet

Abstract

OBJECTIVE: To quantify microbial contamination of human milk purchased via the Internet as an indicator of disease risk to recipient infants. METHODS: Cross-sectional sample of human milk purchased via a popular US milk-sharing Web site (2012). Individuals advertising milk were contacted to arrange purchase, and milk was shipped to a rented mailbox in Ohio. The Internet milk samples (n = 101) were compared with unpasteurized samples of milk donated to a milk bank (n = 20). RESULTS: Most (74%) Internet milk samples were colonized with Gram-negative bacteria or had >104 colony-forming units/mL total aerobic count. They exhibited higher mean total aerobic, total Gram-negative, coliform, and Staphylococcus sp counts than milk bank samples. Growth of most species was positively associated with days in transit (total aerobic count [log10 colony-forming units/mL] β = 0.71 [95% confidence interval: 0.38–1.05]), and negatively associated with number of months since the milk was expressed (β = −0.36 [95% confidence interval: −0.55 to −0.16]), per simple linear regression. No samples were HIV type 1 RNA-positive; 21% of Internet samples were cytomegalovirus DNA-positive. CONCLUSIONS: Human milk purchased via the Internet exhibited high overall bacterial growth and frequent contamination with pathogenic bacteria, reflecting poor collection, storage, or shipping practices. Infants consuming this milk are at risk for negative outcomes, particularly if born preterm or are medically compromised. Increased use of lactation support services may begin to address the milk supply gap for women who want to feed their child human milk but cannot meet his or her needs.

Human milk sharing practices in the U.S.

“…These results are consistent with findings from a recent survey conducted in central Florida in which milk sharing was highly localized, involving online and offline interactions, multiple types of social relationships and sharing of expressed milk simultaneously with cross‐nursing (Reyes‐Foster et al 2015). The social networks and screening interactions reflected in these studies are discordant with the type of anonymous interactions reported in studies of human milk purchased online (Geraghty et al 2013; Keim et al 2013, 2015; Keim et al . 2014a,b).…”

“…The relative risks and benefits of human milk sharing have been the subject of numerous editorials, commentaries and a growing scientific literature (Arnold, 2009; Cohen et al 2010; Landers & Updegrove 2010; Akre et al 2011; Geraghty et al 2011; Gribble & Hausman 2012; Nelson 2012; Brent 2013; Geraghty et al 2013; Keim et al 2013, 2015; Landers & Hartmann 2013; Updegrove 2013a,b; Gribble 2014c; Keim et al . 2014a,b; Martino & Spatz 2014; Carter et al 2015).…”

“…One concern has been that shared milk is being sought primarily for critically ill infants (Geraghty et al 2011; Nelson 2012; Keim et al 2013; Keim et al . 2014a,b).…”

“…2014a,b). Two studies, in which the content of online requests for milk were examined, found that parents commonly indicated they were seeking milk for an infant with ‘a poor birth outcome or other medical condition, which may put them at increased infection risk’ (Keim et al 2013) or child health problems ranging from ‘mild including colds and general immunity, to more severe problems, including necrotizing enterocolitis complications and terminal illness’ (Perrin et al 2014). These studies relied on online posts to draw broad conclusions about milk sharing practices, without accounting for the fact that these public postings are merely an entry point for private milk sharing interactions.…”

“…The terms milk sharing and milk selling are often used interchangeably, underscoring a commonly held misconception that these two practices are enacted in similar ways and carry equivocal risks (Geraghty et al 2013; Keim et al 2013; Keim et al . 2014a,b).…”