title: Inactivation of Cronobacter spp. (Enterobacter sakazakii) in infant formula using lactic acid, copper sulfate and monolaurin.
abstract: OBJECTIVE
  To investigate the effect of lactic acid (LA), copper (II), and monolaurin as natural antimicrobials against Cronobacter in infant formula.
  
  
  RESULTS
  The effect of LA (0.1, 0.2 and 0.3% v/v), copper (II) (10, 50 and 100 microg ml(-1)) and monolaurin (1000, 2000, and 3000 microg ml(-1)) suspended into tween-80 or dissolved in ethanol against Cronobacter in infant formula was investigated. Reconstituted infant formula and powdered infant formula were inoculated with five strains of Cronobacter spp. at the levels of c. 1 x 10(6) CFU ml(-1) and 1 x 10(3) CFU g(-1), respectively. LA at 0.2% v/v had a bacteriostatic effect on Cronobacter growth, whereas 0.3% v/v LA resulted in c. 3 log(10) reduction. Copper (II) at the levels of 50 microg ml(-1) and 100 microg ml(-1) elicited c. 1 and 2 log(10) reductions, respectively. The combination of 0.2% LA and 50 microg ml(-1) copper (II) resulted in a complete elimination of the organism. Monolaurin exhibited a slight inhibitory activity against Cronobacter (c. 1.5 log(10) difference) compared to the control when ethanol was used to deliver monolaurin.
  
  
  CONCLUSIONS
  A complete elimination of Cronobacter was obtained when a combination of sublethal concentrations of LA (0.2%) and copper (II) (50 microg ml(-1)) was used.
  
  
  CONCLUSIONS
  The use of the synergistic interactive combination of LA and copper (II) could be beneficial to control Cronobacter in the infant formula industry.
authors.affiliation: Department of Clinical Nutrition and Dietetics, Faculty of Allied Health Sciences, Hashemite University, Zarqa, Jordan. murad@hu.edu.jo
authors.forename: M A
authors.initials: MA
authors.lastname: Al-Holy
authors.forename: L F
authors.initials: LF
authors.lastname: Castro
authors.forename: H M
authors.initials: HM
authors.lastname: Al-Qadiri
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D019327:Copper Sulfate / Q000494:pharmacology*; D044083:Cronobacter sakazakii / Q000187:drug effects / Q000254:growth & development*; D004755:Enterobacteriaceae / Q000187:drug effects / Q000254:growth & development; D005516:Food Microbiology; D006801:Humans; D007223:Infant; D041943:Infant Formula; D019344:Lactic Acid / Q000494:pharmacology*; D007848:Laurates / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D050178:Monoglycerides / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D007848:Laurates; D050178:Monoglycerides; C020777:monolaurin; D019344:Lactic Acid; D019327:Copper Sulfate