Pure Milk: Developing a low-cost, sustainable biosensor for quantifying bacteria in human breast milk


Human milk is far more than a static source of nutrition. The nutritional content of the milk is dynamic and tailored to fit the state of the infant needs, with varying concentrations of macro- and micro nutritional compounds. [1] Maternal antibodies and numerous other bioactive components delivered through breast milk plays a key role in the protection from infective pathogens, due to the immature acquired immunity of the infant. [2,3]

In the UK, it is estimated that 2-8% of the mothers cannot for physical reasons produce enough milk, while 19% of those who can, choose not to for societal reasons. [4] For those who do not produce the milk for their infant themselves, two options remains: donor milk or formula. The focus on the consequences from exclusively feeding with formula has increased. Stuebe et al. reported in a large case control study, that exclusively formula fed babies have increased incidences of numerous diseases, including gastrointestinal infections (increased by 2.8 fold), respiratory tract infections (increased by 3.6 fold), diabetes (increased by 1.6 fold) and sudden infant death syndrome (increased by 1.3 fold), among others. [5] Donor milk acquired from hospitals are expensive (1000DKK/L), mainly due to the cost of the bacterial analysis, which are performed of hospital premises. The analysis delays the milk up to three days, and cost 500 DKK per test. Donor milk acquired from private donors are usually significantly less expensive or for free, but are not subjected to any quality assurance and hence pose a serious threat to infant health.  Geraghty et al. show that 74% of milk acquired from private donors from online milk sharing websites contained gram negative bacteria at concentrations above 104 CFU, [6]. Studies show that preterm and immune-comprised infants developing late onset neonatal sepsis attributed to group b streptococci, gram-negative bacteria and methicillin –resistant staphylococcus due to pathogenic milk, may have fatal consequences. [7-9] In summary, while quality assured human milk in theory is the optimal source of nutrition, tools for low-cost analysis are missing, creating a gap and a current unmet need.


The aim of this project is to develop a state-of-the-art, sustainable and low-cost technology for the quantification of pathogenic concentrations of bacteria in human breast milk. Results should be provided to the end-user within 30 minutes from applying sample matrices, with a reduction in price per test to 5% of current method. In the long term, the device will be adapted to a home-use test. If the increasing tendency of buying milk on online platforms from private donors remains, this test would give a strong indication of whether the milk is safe for a baby to drink.


  1. O. Ballard, A.L. Morrow, Pediatr Clin North Am. 2013 February ; 60(1): 49–74. doi:10.1016/j.pcl.2012.10.002.
  2. Morrow AL, Ruiz-Palacios GM, Jiang X, Newburg DS. Human-milk glycans that inhibit pathogen binding protect breast-feeding infants against infectious diarrhea. The Journal of nutrition. 2005;135(5):1304–1307.
  3. Turfkruyer M & Verhasselt V (2015) Breast milk and its impact on maturation of the neonatal immune system. Curr Opin Infect Dis 28, 199–206
  4. https://yournaturalbirth.co.uk/2015/06/02/why-most-women-cant-breastfeed/, visited 14-01-2020
  5. Rao et al. ‘The risk of not breastfeeding for mothers and infants’ MedRevews, LLC, vol 2,4, 2009
  6. Geraghty et al. ‘Microbial contamination of human milk purchased via the internat’ Pediatrics, vol 132, 5, 2013
  7. Shah et al. ‘Breast milk as a source of late onset neonatal sepsis’, Pediatr Infect Dis J, vol 24, 4, 2005
  8. Paton et al. ‘Gram-negative bacilli in human feedings: quantitation and clinical consequences for premature infants’ J. Pediar. Vol 109, 4, 1986
  9. Weber et al. ‘Transmission of methicillin-resistant staphylococcus aureus to preterm infants through breast milk’ Infect Control Hosp Epidemiol, vol 25, 9, 2004


Winnie Edith Svendsen
DTU Bioengineering
+45 31 25 93 69


Maria Dimaki
Senior Researcher
DTU Bioengineering
+45 45 25 26 61


Lea Holritz
PhD student
DTU Bioengineering


Anne Bille Olin
Clinical Dietician
10 DECEMBER 2023