Heat transfer analysis of staphylococcus aureus on stainless steel with microwave radiation.

PAPER pubmed Journal of applied microbiology 1999 In vitro study Effect: harm Evidence: Low

Read original paper → DOI: 10.1046/j.1365-2672.1999.00832.x PMID: 10540242 Evidence Lab

Abstract

Staphylococcus aureus (NCTC 6571; Oxford strain) on stainless steel discs was exposed to microwave radiation at 2450 MHz and up to 800 W. Cell viability was reduced as the exposure time increased, with complete bacterial inactivation at 110 s, attaining a temperature of 61.4 degrees C. The low rate of temperature rise, RT, of the bacterial suspension as compared with sterile distilled water or nutrient broth suggests a significant influence of the microwave sterilization efficacy on the thermal properties of the micro-organisms. The heat transfer kinetics of thermal microwave irradiation suggest that the micro-organism has a power density at least 51-fold more than its surrounding liquid suspension. When the inoculum on the stainless steel disc was subjected to microwave radiation, heat conduction from the stainless steel to the inoculum was the cause of bacteriostasis with power absorbed at 23.8 W for stainless steel and 0.16 W for the bacteria-liquid medium. This report shows that the microwave killing pattern of Staph. aureus on stainless steel was mainly due to heat transfer from the stainless steel substrate and very little direct energy was absorbed from the microwaves.

AI evidence extraction

At a glance

Study type

In vitro study

Effect direction

harm

Population

—

Sample size

—

Exposure

microwave · 2450 MHz · up to 110 s

Evidence strength

Low

Confidence: 78% · Peer-reviewed: yes

Main findings

Staphylococcus aureus on stainless steel discs exposed to 2450 MHz microwave radiation (up to 800 W) showed reduced viability with increasing exposure time, with complete inactivation at 110 s when temperature reached 61.4b0C. The report concludes the killing pattern was mainly due to heat transfer from the stainless steel substrate, with little direct microwave energy absorbed by the bacteria-liquid medium.

Outcomes measured

Cell viability / bacterial inactivation
Temperature rise / heat transfer kinetics
Power absorbed by stainless steel vs bacteria-liquid medium
Bacteriostasis on stainless steel discs

Limitations

In vitro study on a specific bacterial strain on stainless steel discs; findings may not generalize beyond this setup.
No sample size or replication details provided in the abstract.
Exposure metrics beyond frequency, power, and time (e.g., field strength, dosimetry/SAR) are not reported in the abstract.

View raw extracted JSON

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": "up to 110 s"
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "Cell viability / bacterial inactivation",
        "Temperature rise / heat transfer kinetics",
        "Power absorbed by stainless steel vs bacteria-liquid medium",
        "Bacteriostasis on stainless steel discs"
    ],
    "main_findings": "Staphylococcus aureus on stainless steel discs exposed to 2450 MHz microwave radiation (up to 800 W) showed reduced viability with increasing exposure time, with complete inactivation at 110 s when temperature reached 61.4\u0000b0C. The report concludes the killing pattern was mainly due to heat transfer from the stainless steel substrate, with little direct microwave energy absorbed by the bacteria-liquid medium.",
    "effect_direction": "harm",
    "limitations": [
        "In vitro study on a specific bacterial strain on stainless steel discs; findings may not generalize beyond this setup.",
        "No sample size or replication details provided in the abstract.",
        "Exposure metrics beyond frequency, power, and time (e.g., field strength, dosimetry/SAR) are not reported in the abstract."
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "Staphylococcus aureus",
        "stainless steel",
        "microwave radiation",
        "2450 MHz",
        "heat transfer",
        "thermal effects",
        "bacterial inactivation",
        "sterilization",
        "power absorption"
    ],
    "suggested_hubs": []
}

AI can be wrong. Always verify against the paper.

AI-extracted fields are generated from the abstract/metadata and may be incomplete or incorrect. This content is for informational purposes only and is not medical advice.

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