Abstract
Microbial contamination of food can lead to faster spoilage and infections. Therefore, disinfection processes are required that have a low detrimental effect on the nutritional content. Concerning radiation disinfection, two spectral ranges have recently become important. The Far-UVC spectral range, with a wavelength below 230 nm and visible violet light. In this study, leaf spinach was used to investigate the extent to which these radiations inactivate Escherichia coli, but also to determine if the vitamin C or chlorophyll content was reduced. Frozen spinach leaves (Spinacia oleracea) were contaminated with E. coli × pGLO and irradiated with either a 222 nm krypton chloride lamp or 405 nm LEDs. The achieved bacterial reduction was determined by plating the irradiated samples on agar plates and subsequent colony counting. The vitamin C concentration was determined by means of redox titration, and the concentrations of chlorophyll a and chlorophyll b were determined using spectrometry. Both irradiations exhibited a strong antimicrobial impact on E. coli. The average log reduction doses were about 19 mJ/cm2 (222 nm) and 87 J/cm2 (405 nm), respectively. The vitamin C concentration decreased by 30% (222 nm) or 20% (405 nm), and the chlorophyll concentrations decreased by about 25%. Both irradiation approaches are able to substantially reduce microorganisms on spinach leaves by two orders of magnitude, but this is associated with a reduction in the nutrient content.
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Claims 7
Claim · model-written summary
Both irradiation wavelengths strongly reduced E. coli on spinach leaves.
- Taxon
- Spinacia oleracea
Spinacia oleraceae1 - Treatment
- 222 nm krypton chloride lamp or 405 nm LEDse1
- Interactor
- E. coli
.jpg?width=60)
Escherichia colie0pathogen - Outcome
- antimicrobial impact on E. colie0
- Direction
- stronge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Both irradiations exhibited a strong antimicrobial impact on E. coli”
e1“spinach leaves (Spinacia oleracea) were contaminated with E. coli × pGLO and irradiated with either a 222 nm krypton chloride lamp or 405 nm LEDs”
Claim · model-written summary
The average log reduction dose for 222 nm irradiation was about 19 mJ/cm2.
- Taxon
- Spinacia oleraceaSpinacia oleraceae1
- Treatment
- 222 nme0
- Interactor
- E. coliEscherichia colie1pathogen
- Outcome
- log reduction dosese0
- Value
- 19 mJ/cm2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average log reduction doses were about 19 mJ/cm2 (222 nm) and 87 J/cm2 (405 nm), respectively”
e1“spinach leaves (Spinacia oleracea) were contaminated with E. coli × pGLO”
Claim · model-written summary
The average log reduction dose for 405 nm irradiation was 87 J/cm2.
- Taxon
- Spinacia oleraceaSpinacia oleraceae1
- Treatment
- 405 nme0
- Interactor
- E. coliEscherichia colie1pathogen
- Outcome
- log reduction dosese0
- Value
- 87 J/cm2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average log reduction doses were about 19 mJ/cm2 (222 nm) and 87 J/cm2 (405 nm), respectively”
e1“spinach leaves (Spinacia oleracea) were contaminated with E. coli × pGLO”
Claim · model-written summary
Vitamin C concentration decreased by 30% after 222 nm irradiation.
- Taxon
- Spinacia oleraceaSpinacia oleraceae1
- Treatment
- 222 nme0
- Outcome
- vitamin C concentratione0
- Direction
- decreasede0
- Value
- 30%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The vitamin C concentration decreased by 30% (222 nm) or 20% (405 nm)”
e1“spinach leaves (Spinacia oleracea)”
Claim · model-written summary
Vitamin C concentration decreased by 20% after 405 nm irradiation.
- Taxon
- Spinacia oleraceaSpinacia oleraceae1
- Treatment
- 405 nme0
- Outcome
- vitamin C concentratione0
- Direction
- decreasede0
- Value
- 20%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The vitamin C concentration decreased by 30% (222 nm) or 20% (405 nm)”
e1“spinach leaves (Spinacia oleracea)”
Claim · model-written summary
Chlorophyll concentrations decreased by about 25% after irradiation.
- Taxon
- Spinacia oleraceaSpinacia oleraceae2
- Treatment
- irradiationse1
- Outcome
- chlorophyll concentrationse0
- Direction
- decreasede0
- Value
- 25%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the chlorophyll concentrations decreased by about 25%”
e1“Both irradiations exhibited a strong antimicrobial impact on E. coli”
e2“spinach leaves (Spinacia oleracea)”
Claim · model-written summary
The irradiation approaches reduced microorganisms on spinach leaves by two orders of magnitude.
- Taxon
- Spinacia oleraceaSpinacia oleraceae1
- Treatment
- irradiation approachese0
- Outcome
- microorganisms on spinach leavese0
- Direction
- reducee0
- Value
- two orders of magnitudee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both irradiation approaches are able to substantially reduce microorganisms on spinach leaves by two orders of magnitude”
e1“spinach leaves (Spinacia oleracea)”
The same questions in other papers
radiation · physiology: pigments · Spinacia oleracea (spinach)Results agree
3 papers in the same direction as this paper
- no effect
- negative
- negative
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.