Metal ions reverse the inhibitory effects of selected food-grade phosphates in Staphylococcus aureus

• Published in: Journal of food protection 1994-04, Vol.57 (4), p.284-288
• Main Authors: Lee, R.M, Hartman, P.A, Olson, D.G, Williams, F.D
• Format: Article
• Language: English
• Subjects: ALIMENTOS; Biological and medical sciences; CATION; CATIONES; Food industries; Food microbiology; FOSFATOS; Fundamental and applied biological sciences. Psychology; INHIBICION; INHIBITION; METAL; METALES; PHOSPHATE; PRODUIT ALIMENTAIRE; PROPIEDADES ANTIMICROBIANAS; PROPRIETE ANTIMICROBIENNE; STAPHYLOCOCCUS AUREUS
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-57.4.284

Previous studies showed that levels as low as 0.1% sodium ultraphosphate (UP), 0.1% sodium polyphosphate glassy (SPG) and 0.5% tetrasodium pyrophosphate (TSPP) were bactericidal and bacteriolytic to early-exponential phase cells of Staphylococcus aureus ISP40 8325. In the present study, Ca(2+) (0.01 M) or Mg(2+) (0.01 M) reversed the bacteriolytic effects of UP (0.1%) and SPG (0.1%) to S. aureus. In addition, Ca(2+) (0.01 M) or Mg(2+), (0.01 M), when added to the culture medium before inoculation, protected cells from growth inhibition by UP and SPG. Moreover, the bactericidal effects of UP or SPG were reversed by Ca(2+) or Mg(2+), in metal-rescue experiments in which the metals were added to polyphosphate-containing medium after 1 h of incubation. No additive effect existed between Mg(2+) and Ca(2+). Growth inhibition of TSPP was not reversed by Mg(2+) or Ca(2+), but it was reversed by Fe(3+) when Fe(3+) was added to protect cells 1 h before the addition of TSPP. These studies show that the antibacterial effects of phosphates can be altered substantially by the metal-ion content of the environment