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Bactericidal and Bacteriolytic Effects of Selected Food-Grade Phosphates, Using Staphylococcus aureus as a Model
Ruby M Lee1, Paul A Hartman1, Dennis G Olson1
1Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa 50011.
Journal of Food Protection
|May 23, 2019
Summary
Longer chain phosphates like sodium ultraphosphate show stronger antimicrobial properties against Staphylococcus aureus. These phosphates cause cell lysis, releasing intracellular components and forming aggregates.
Area of Science:
- Food Science
- Microbiology
- Biochemistry
Background:
- Phosphates are utilized in meat products for flavor enhancement and yield increase.
- Phosphates are recognized for their antimicrobial capabilities.
Purpose of the Study:
- To investigate and compare the antimicrobial effects of various food-grade phosphates.
- To determine the minimum inhibitory concentrations (MICs) of different phosphates against Staphylococcus aureus.
Main Methods:
- Determining MICs of sodium ultraphosphate, sodium polyphosphate glassy, sodium acid pyrophosphate, sodium tripolyphosphate, and tetrasodium pyrophosphate.
- Utilizing spectrophotometry and microscopy to observe cellular changes and nucleotide leakage.
- Analyzing cellular aggregates using DNase, RNase, and proteinase.
Main Results:
- Lower MICs (0.1%) were observed for long-chain phosphates (sodium ultraphosphate, sodium polyphosphate glassy) compared to shorter-chain phosphates (0.5%).
- Phosphate treatment led to the leakage of intracellular nucleotides, indicated by A260-absorbing material.
- Microscopic examination revealed gelatinous cellular aggregates containing DNA, RNA, and protein, signifying cell lysis.
Conclusions:
- Chain length influences the antimicrobial efficacy of phosphates, with longer chains being more potent.
- Phosphates induce cell lysis in Staphylococcus aureus, leading to the release of cellular components.
- The antimicrobial action of phosphates involves disruption of cell integrity.
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