CERTIFICATE Inactivation of bacteria, viruses and other pathogens ...

ecoscope Hochgratweg 12 D-88279 Amtzell 

1. Summary 

CERTIFICATE 

- page 1 of 17 - 

Priv. Doz. Dr. Ingo Maier - Dr. Ulrike Plum 

Hochgratweg 12 

D-88279 Amtzell 

Tel. 07520-953 660 

Fax 07520-953 661 

info@ecoscope.de 

www.ecoscope.de 

Inactivation of bacteria, viruses and other pathogens 

by UVC irradiation 

in the Leica cryostat product family 

UVC radiation is effective in disinfecting surfaces and air within the irradiated working 

space of the cryostats Leica CM1850UV, CM1900UV and CM1950 at -20 °C (Table 1). 

For high-level disinfection, irradiation for three hours (CM1850UV/CM1950) and four 

hours (CM1900UV) is recommended. Vegetative bacteria including Mycobacterium 

tuberculosis, bacterial endospores (Bacillus sp.) and fungi are inactivated within this 

period of time. Viruses are also inactivated by at least 4 log10 units (99,99 %), including 

resistent species like hepatitis viruses. 

Intermediate level disinfection can be achieved by short-term irradiation of 30 minutes 

(CM1850UV/CM1950) and 40 minutes(CM1900UV). This reduces vegetative bacteria 

including Mycobacterium tuberculosis and sensitive viruses like Influenza A virus 

(including highly pathogenic avian influenza A type H5N1 viruses) and Poliovirus by at 

least 5 log10 units (99,999%). 

UVC irradiation within the working space of the cryostats can provide safe and 

effective surface and air disinfection and significantly reduces infection risk. 

It is recommended to wipe off visible contamination in the cryostat with an alcoholic 

based disinfectant before using the UV lamp. The germicidal effect of radiation is 

restricted to directly illuminated areas. Therefore, UVC irradiation cannot replace 

regular chemical disinfection of the cryostat chamber. 

Amtzell, 31 October 2007 

Ingo Maier, PhD, PD 

ecoscope does not accept any responsibility for misleading citations due to incomplete 

reproduction of this certificate.

Table 1: Predicted UVC disinfection efficacy 1 for selected pathogens in the cryostats 

Leica CM1850UV/CM1950 and CM1900UV 2 

Species 

Bacteria 3 

Bacillus ssp. (spores) 

page 2 of 17 

Irradiation time 2 

30 min / 40 min 3 h / 4 h 

Enterobacter faecium yes yes 

Escherichia coli yes 

Klebsiella pneumoniae yes yes 

Mycobacterium tuberculosis yes 

Proteus mirabilis yes yes 

Pseudomonas aeruginosa yes 

Salmonella sp. ser. enteritidis yes yes 

Salmonella sp. ser. typhimurium yes 

Staphylococcus aureus yes yes 

Vibrio cholerae yes 

Yeasts 3 and moulds 3 

Aspergillus fumigatus (spores) 

Candida albicans yes 

Cryptococcus neoformans 

Viruses 4 

Adenoviruses 

Hepatitis A virus yes 

Hepatitis B virus 

Herpes viruses yes 

Influenza viruses yes 

Poliovirus yes 

SARS coronavirus 

Simian virus 40 

Vaccinia virus yes 

yes: disinfection achieved 

1: valid only for conditions equivalent to those in the tests 

2 : 40 min/4h irradiation periods apply to the cryostat CM1900UV 

3 : reduction by 5 log10 units (bacteria, fungi incl. yeasts) 

4 : reduction by 4 log10 units (viruses) 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes

2. Experimental basis 

Leica Microsystems Nussloch GmbH (now Leica Biosystems Nussloch GmbH, Nussloch, 

Germany) contracted the laboratory ecoscope Priv. Doz. Dr. Ingo Maier (Amtzell, Germany) 

in 2004 to evaluate the surface disinfection efficacy of ultraviolet irradiation in the cryostat 

CM1850. The apparatus was equipped with a low pressure mercury arc lamp (SterilAir, 

Kreuzlingen, Switzerland). 

The evaluation consisted of determining the inactivation by UVC light (254 nm) irradiation of 

test bacteria and viruses on stainless steel surfaces in the cryostat chamber at -20 °C 

(display). 

In a first project, the bacterium Staphylococcus aureus ATCC 6538 was used as a 

biodosimetry strain. Bacteria were dried onto stainless steel plates from suspensions in 

distilled water. The germ carriers were placed into different, defined positions within the 

cryostat chamber. The results (EcoScope 2004a) indicated that under the specified test 

conditions, UV irradiation was capable of inactivating S. aureus by >5 log10 units after 15 - 30 

min irradiation, depending on the test position. 

In two independent experimental series, the inactivation of the test virus Simian virus 40 (SV 

40, a polyomavirus) exposed to UVC for different periods of time was investigated. Viruses 

suspended in cell culture medium containing 2 % bovine fetal serum were dried onto 

stainless steel plates. The virus carriers were placed in a fixed position in the cryostat 

chamber. After irradiation, the viruses were rinsed off and in blind tests applied to monkey 

kidney cell cultures (CV-1) for virus propagation. After 12-14 and 15-18 days incubation, the 

cell cultures were examined for virus-specific cytopathic effects and the infectivity titres were 

determined. The results were presented in a separate test report (EcoScope 2004b). It was 

shown that the inactivation of SV 40 by >4 log10 units was achieved by UV irradiation for 95 - 

180 minutes. 

Leica Microsystems Nussloch GmbH supplied comparative measurements of UVC intensities 

at differents positions in the working spaces of the cryostats CM1850UV, CM1950 and 

CM1900UV. 

On the basis of these experimental results and available scientific information the inactivating 

effect of UVC irradiation in the cryostats on pathogenic microorganisms and viruses could be 

assessed (Table 1). Literature data on UVC (254 nm) radiation doses required for the 

inactivation of various microorganisms and viruses are summarized in appendix I. 

3. The mechanism of UV damage 

Low pressure mercury arc lamp radiation is essentially monochromatic with an peak output 

at 253.7 nm, close to the absorption maximum of nucleic acids (DNA, RNA), the carrier of 

genetic information. Absorption of UV photon energy causes photochemical damage in 

micro-organisms by formation of lesions, in particular through dimerization of adjacent 

pyrimidine nucleotides. Accumulated lesions may overwhelm the cellular capacity for repair, 

induce mutations, inhibit replication and thus finally kill the organism (Friedberg et al. 1995). 

page 3 of 17

4. Influence of nucleic acid conformation on UV resistance 

Nucleic acids in viral genomes may have different conformations: single-stranded DNA resp. 

-RNA (ssDNA resp. ssRNA) or double-stranded DNA resp. -RNA (dsDNA resp. dsRNA). In 

inactivation experiments on ssRNA and dsRNA obtained from the same virus it was shown 

that ssRNA is more sensitive against UVC radiation than dsRNA (Bishop et al. 1967, 

Závadová et al. 1968). The same is true for ssDNA and dsDNA (Abraham P. J. & van der Eb 

A. J. 1976, Jansz et al. 1963, van der Eb & Cohen 1967, Yarus & Sinsheimer 1964). DNA 

viruses are more sensitive than RNA viruses. These results are supported by available data 

on UV inactivation: ssRNA viruses like Caliciviridae, Orthomyxoviridae, Picornaviridae and 

Togaviridae are entirely highly sensitive, whereas dsRNA- and dsDNA viruses of comparable 

genome size (Adenoviridae, Reoviridae, Polyomaviridae) are clearly more resistant to UVC 

(Table 2). The differences in sensitivity most probably reflect different capacities for host cell 

repair. 

5. Kinetics of UV inactivation in microorganisms 

Germicidal UV irradiation inactivates pathogens according to the standard decay equation 

S = exp (-k*I*t). In this equation, S represents the fraction of the original population that 

survives exposure at time t, and I represents the light intensity. Mathematical modeling of UV 

decay curves has been reviewed by Kowalski et al. (2000). 

The rate constant k and lethal ultraviolet dosages (I*t) have been determined experimentally 

for a large number of bacteria, fungi, viruses and protozoa in numerous studies. UVC doses 

required for the inactivation of a selection of microorganisms, especially viruses, are given in 

appendix I. Although the results vary depending on experimental design, UV measurement 

and state of the biological material, a conclusive picture of relative UV sensitivities has been 

obtained. By use of biodosimetry test strains, conclusions about UV dosages can be drawn 

and predictions made on their effect on other organisms (Lytle & Sagripanti 2005). 

6. Staphylococcus aureus as a test bacterium 

Staphylococcus aureus 6538 has been chosen as test strain, because it is one of the listed 

test strains in standardized disinfection testing and a potential pathogen in humans. In 

addition, data on the UVC sensitivity of S. aureus are available from the scientific literature 

(Appendix I). 

7. SV 40 as a surrogate virus in disinfection testing 

A surrogate virus employed in the testing of disinfection methods should respond to the 

disinfectant in question in a similar way as the pathogen against which it was designed. At 

best, the surrogate virus should be somewhat more resistant. Among the different virus 

groups, small dsDNA viruses show the highest resistance against UVC. 

SV 40 was chosen as test virus because of several advantageous properties. It is a relatively 

small virus (ca. 50 nm) possessing a small genome of dsDNA (5.2 kbp) and a very high 

resistance to UVC radiation (see appendix I). SV 40 propagates in mammalian cells 

(monkey, man). It is classified in risk class 2 and can thus be handled at reasonable 

expense. The virus and a suitable test system (monkey kidney cells) are available. SV 40 is 


iochemically and genetically well characterized. Moreover, SV 40 is one of the test viruses 

in the standardized testing of chemical disinfectants against viruses (Bundesgesundheitsamt 

1982, 1990). Contrary to the European standard (BS EN 14676, DIN EN 14476), the German 

Federal Health Office (Robert Koch Institute) demands tests on SV 40 in addition to 

Poliovirus and Adenovirus because it proved to be more resistant in some investigations 

(RKI, DVV & DGHM 2004). 

SV 40 is among the viruses most resistant to UVC, surpassing vegetative bacteria and 

bacterial spores (appendix I). Scientific data prove that ssRNA- and ssDNA viruses are 

inactivated faster, as well as large dsDNA viruses like herpes viruses and Vaccinia virus, for 

example. Among the small dsDNA viruses, adenoviruses are more sensitive to UVC than 

polyomaviruses including SV 40. Hepatitis B virus is of similar size as SV 40 (Table 2) and 

therefore, a similar or higher sensitivity to UVC is postulated. Presence or absence of an viral 

envelope is irrelevant in relation to UVC sensitivity. In conclusion, SV 40 is regarded as a 

suitable surrogate for pathogenic viruses in UVC inactivation studies. 

Table 2: Overview on important viruses infecting humans and predicted UVC 

sensitivity 

virus family 

genome 

type 

enve- 

lope 

genome 

size 

(kb/kbp) 


D90 

(mWcm -2 ) 

virus 

Adenoviridae dsDNA no 28-45 27-49 Human adenovirus A to F 

Arenaviridae ssRNA yes 10-11 3.5 Lassa virus 

Astroviridae ssRNA no 6.8 10-12 Astrovirus 

Bunyaviridae ssRNA yes 11-12 2.0-3.5 

California encephalitis 

virus 

Hantaan virus 

Caliciviridae ssRNA no 7.5 9.7-11 Norwalk virus (NoV) 

Sapporo virus 

Hepatitis E virus 

Coronaviridae ssRNA yes 30 0.7-1.1 SARS coronavirus 

Deltaviridae ssRNA yes 1.7 22 

Hepatitis D virus (assoc. 

to HBV) 

Filoviridae ssRNA yes 19.1 2.0 

viruses causing 

haemorrhagic fevers: 

Marburg-, Ebola virus 

Flaviviridae ssRNA yes 10-12 6.8-8.4 Hepatitis C virus 

Yellow fever virus 

Tick-borne encephalitis 

virus 

Hepadnaviridae dsDNA yes 3.2 3.8-4.1 Hepatitis B virus (HBV) 

Herpesviridae dsDNA yes 125-235 3.5-7.0 Herpes simplex virus 1, 2 

Varicella zoster virus 

Cytomegalovirus 

Epstein Barr virus 

Human herpes virus 6, 7 

Human herpes virus 8 

Orthomyxoviridae ssRNA yes 13.6 2.0-3.0 Influenza virus A-C

Papovaviridae dsDNA no 5-8 68-103 Polyomavirus 

Papillomavirus (warts) 

Paramyxoviridae ssRNA yes 15-16 3.0 Measles virus 

Mumps virus 

Parainfluenza virus 

Human respiratory 

syncytial virus 

Parvoviridae ssDNA no 5.5 2.1-3.2 Parvovirus B19 

Picornaviridae ssRNA no 7-8 12-14 Hepatitis A virus (HAV) 

Poliovirus 

Coxsackievirus 

Echovirus 


Rhinovirus 

Poxviridae dsDNA yes 130-375 1.8-4.3 

Smallpox virus, 

molluscum contagiosum 

Reoviridae dsRNA no 16-27 19-32 Reovirus 

Human rotavirus A, B 

Retroviridae ssRNA yes 7-11 18-30 

Human 

immunodeficiency virus 

(HIV) types 1 and 2 

Human T-lymphotropic 

viruses (HTLV-1, -2) 

Rhabdoviridae ssRNA yes 12 0.9-1.2 Rabies virus 

Togaviridae ssRNA yes 10-12 4.9-6.5 Rubella virus 

Table 2: 

Morphological characters apply to the respective virus family. 

abbreviations 

D90: UVC dose required for 90% inactivation (1 log10 unit reduction) 

dsDNA: double-stranded desoxyribonucleic acid 

dsRNA: double-stranded ribonucleic acid 

kb/kbp: x 1000 (kilo) bases resp. basepairs 

nm: nanometer = 10 -9 m 

ssDNA: single-stranded desoxyribonucleic acid 

ssRNA: single-stranded ribonucleic acid 

The list of viruses was compiled according to a corresponding list published by the Robert 

Koch Institute in cooperation with the German Association for the Control of Virus Diseases 

and the German Society for Hygiene and Microbiology (RKI, DVV, DGHM 2004), according 

to the U.S. Departments of Health and Human Services (CDC 2004) and Büchen-Osmond 

2003a, b). The predicted values for UVC sensitivity were adopted from Lytle & Sagripanti 

(2005).

8. Disinfection: definitions 

The guidelines of the German Society for Hygiene and Microbiology (DGHM, 1991) for the 

evaluation of chemical surface disinfectants provide that bacteria and fungi are usually 

inactivated by a factor of at least 5 log10 units. This corresponds to the European standard 

EN 1040 on the testing of chemical disinfectants in suspension tests (phase 1). 

For the certification of virus disinfection, the guidelines of the German Association for the 

Control of Virus Diseases (Bundesgesundheitsamt 1990, DVV 1997) for chemical surface 

disinfection require a reduction in infectivity by minimum 4 log10 units. 

In addition, the following classification scheme of disinfection levels are used: 

1. Low-level disinfection can kill most bacteria, some viruses, and some fungi, but it cannot 

be relied on to kill resistant microorganims such as Mycobacterium tuberculosis or bacterial 

spores. 

2. Intermediate-level disinfection inactivates Mycobacterium tuberculosis, vegetative 

bacteria, most viruses, and most fungi, but it does not necessarily kill bacterial spores. 

3. High-level disinfection: Destruction of all microorganisms, with the exception of high 

numbers of bacterial spores. 

4. Sterilisation: Complete elimination of microorganisms and viruses. 

These definitions are used by the U. S. Department of Health and Human Services 

(CDC 1986, 2003), the Association for Professionals in Infection Control and Epidemiology 

(APIC, Rutala 1996), the WHO (WHO 1999, 2003) and others. 

The standards refer to the effectiveness of chemical disinfectants. In analogy, they are 

applied to surface disinfection by UVC irradiation in the following. 

9. Effectiveness of disinfection by UVC irradiation 

Inactivation experiments with Staphylococcus aureus ATCC 6538 showed that the number of 

viable bacteria was reduced by more than 5 log10 units after irradiation for 30 minutes in the 

cryostat CM1850UV. The disinfection efficacy corresponded to the guideline of the German 

Society for Hygiene and Microbiology (DGHM, 1991) for surface disinfection methods and to 

an intermediate-level disinfection as defined above. 

Disinfection of vegetative bacteria (≥5 log10 units reduction) including Staphylococcus aureus 

is achieved by UV-C dosages of ≤41 mWs cm -2 (appendix I). No literature data are available 

for S. aureus ATCC 6538. However, it is not to be expected that the test strain differs 

significantly in sensitivity from other S. aureus strains. The UV sensitivity of Mycobacterium 

terrae, the surrogate organism for M. tuberculosis in disinfectant testing, has not been 

reported. Therefore, M. tuberculosis was included in table 1. The similarity in the UV 

response allows the prediction that disinfection of all vegetative bacteria listed in table 1 is 

achieved by 30 minutes or 40 minutes UV irradiation. In contrast, spore-forming bacteria like 

Bacillus subtilis and B. anthracis are not inactivated to the same extent, in particular because 

the increased sensitivity of frozen cells does not apply for spores. 


While the UV sensitivity of the yeast Candida albicans compares to that of vegetative 

bacteria, Aspergillus spores and the melanized form of Cryptococcus neoformans are highly 

resistent to UV irradiation. 

Within the given experimental conditions, an inactivation of the test virus SV 40 by minimum 

4 log10 units was achieved by UV irradiation for 95 minutes and longer in the cryostat 

CM1850UV. This inactivation level corresponds to the accepted guideline of the German 

Association for the Control of Virus Diseases for the effectiveness of disinfectants against 

viruses (DVV 1997). 

An account of the, compared to other pathogens, high resistance of the test virus SV 40 to 

UVC (appendix I), it can be assumed according to the scientific state of knowledge that other 

resistant viruses including hepatitis B virus and fungal spores are inactivated to the same 

extent within the same irradiation time and also that vegetative bacteria including 

Mycobacterium tuberculosis, bacterial spores, fungi, and most viruses are destroyed with 

higher effectivity, as long as they are directly subjected to irradiation on surfaces or in the air 

(Table 1). The inactivation effect can be classified as high-level disinfection as defined 

above. 

The test results showed that the effect of irradiation was considerably affected by 

components of the cell culture medium and the addition of 2 % bovine fetal serum: irradiation 

times above 95 minutes did not result in significantly increased inactivation. This has to be 

seen as an approximation to practical situations. It is recommended, to remove visible 

contamination in the cryostat by wiping with disinfectant before using the UV lamp. For this 

purpose, an alcoholic based disinfectant recommended by the cryostat manufacturer should 

be used. 

Dependent on the position in the cryostat, the radiation dose received by a surface area can 

be less than that in the test position used with SV 40. For disinfecting these areas the 

irradiation time has to be increased proportionally. In consideration of results from the study 

on S. aureus (EcoScope 2004a) and with inclusion of an additional safety margin, a factor of 

1.5 + 0.4 = 1.9 is proposed for prolongation of the irradiation period. Therefore, irradiation for 

3 hours is recommended for high-level disinfection in directly irradiated areas of the cryostat 

chamber of the CM1850UV. Comparative measurements showed that the incident UVC 

radiation on surfaces of the cryostat chamber of the CM1950 reaches the same intensity as 

that in the CM1850UV. Accordingly, irradiation for 30 min is also recommended for an 

intermediate level of disinfection in the CM1950 UV, and 3 hours for high-level disinfection. 

The UVC radiation intensity on surfaces of the cryostat chamber of the CM1900UV is by 25 

% lower than in the CM1850UV. Therefore, 40 min resp. 4 hours irradiation are 

recommended for an intermediate resp. high-level disinfection in th CM1900 UV (Table 1). 

The test results and assessment of disinfection efficacy refer to the full radiation output of a 

lamp such as employed in the test. 

Disinfection at the predicted level is restricted to directly illuminated air and surface areas. 


10. UV inactivation of Avian influenza A/(H5N1) virus 

Avian influenza 

Avian influenza ("bird flu") is an infectious disease of poultry caused by influenza type A 

viruses. An unprecedented epidemic of highly pathogenic avian flu (HPAI) spreads across 

large populations of domestic birds and migratory water fowl in Asia since 2003 and has 

reached Europe in late 2005 (FAO 2005, WHO 2004, 2005). 

Avian influenza viruses do not normally infect humans. However, about 200 people have 

already died from the current epidemic (WHO 2007). This raises serious concerns that 

genetic reassortment with a human flu strain, possibly involving pigs as intermediate hosts, 

will result in the next influenza pandemic with massive fatalities worldwide (Bush 2004, Fleck 

2004, Cyranoski 2005, Khamsi 2005, Williams 2005, Zeitlin & Maslow 2005).Because of this, 

special attention is given here to inactivation of influenza viruses by UVC irradiation. 

Influenza viruses 

Influenza ("flu") viruses are classified into types A, B or C. Humans can be infected by all 

three types. Influenza viruses that infect birds are called “avian influenza viruses”. Only 

influenza type A viruses infect birds. Influenza A viruses can infect people, birds, pigs, 

horses, and other animals, but wild birds are the natural hosts for these viruses. Influenza 

type A viruses are divided into subtypes based on two proteins on the surface of the virus 

called hemagglutinin (H) and neuraminidase (N). There are 14 hemagglutinin subtypes and 9 

neuraminidase subtypes of influenza A viruses, and potentially all H/N-combinations are 

possible. To date, all outbreaks of HPAI have been caused by influenza A viruses of 

subtypes H5 or H7. HPAI is usually associated with high mortality in poultry. 

Influenza viruses are members of the family Orthomyxoviridae. Their genome consists of 

eight segments of linear, single-stranded RNA with a total length of 13,600 nucleotides. 

Influenza viruses are enveloped viruses. In spherical forms, the virion diameter is 80-120 nm. 

UVC inactivation of influenza virus 

Viruses like influenza virus with genomes comprised of single-stranded RNA are particularly 

sensitive to UVC radiation. This is supported by available data on UV inactivation (Table 2, 

Appendix I). Accordingly, the decimal UVC (254 nm) inactivation dose for influenza A virus 

strains has been found to be as low as 1.8 - 4.1 mWs cm -2 and that for the entire virus family 

has been predicted as 2.0 - 3.0 mWs cm -2 . It is thus in the same range as that for vegetative 

bacteria like Escherichia coli and Staphylococcus aureus 12-14 . The susceptibility of influenza 

virus to UVC disinfection has also been noted by Riley (1977). 

The morphology, general structure and genome organization is the same in all influenza 

viruses. Data on UVC sensitivity of human influenza virus strains are thus equally applicable 

to avian influenza viruses including influenza A subtype H5N1. 

It is concluded that a 30 min period of germicidal UVC irradiation in the cryostats CM1850 

UV/CM1950 and a 40 min period in the CM1900UV results in an inactivation of Influenza A 

virus by at least 5 log10 units. This corresponds to high-level disinfection. 


11. References 

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DNA in five complementation groups of xeroderma pigmentosum. Mut. Res. 35: 13-22. 

Bishop J. M., Quintrell N., Koch G. 1967. Poliovirus double-stranded RNA: Inactivation by 

ultraviolet light. J. molec. Biol. 24:125. 

Büchen-Osmond C. 2003a. Taxonomy and classification of viruses. In: Manual of Clinical 

Microbiology, 8th Ed., Vol. 2, pp. 1217-1226, ASM Press, Washington DC. 

Büchen-Osmond C. (ed) 2003b. ICTVdB - The Universal virus database, version 3. ICTVdB 

Management, The Earth Institute and Department of Epidemiology, Mailman School of Public Health, 

Columbia University, New York (http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/index.htm) 

BS EN 14676 (2005). Chemical disinfectants and antiseptics. Virucidal quantitative suspension test for 

chemical disinfectants and antiseptics used in human medicine. Test method and requirements 

(phase 2, step 1). 

Bundesgesundheitsamt 1982. Richtlinie des Bundesgesundheitsamtes und der Deutschen 

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und Antiseptika – Prüfverfahren und Anforderungen (Phase 2, Stufe 1). 


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- October 2005). www.fao.org/ag/againfo/subjects/documents/ai/ AVIbull036.pdf 

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Health Organ. 82(3): 236-237. 

Friedberg E. C., Walker G. C., Siede W. 1995. DNA repair and mutagenesis. American 

Society for Microbiology Press, Washington, DC, 698 S., ISBN 1-55581-088-8 

Jansz H. S., Pouwels P. H., van Rotterdam C. 1963. Sensitivity to ultraviolet light of single and doublestranded 

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Khamsi R 2005. Deadly combinations. Nature 435 (7041): 408 

Kowalski W. J., Bahnfleth W. P., Witham D. L., Severin B. F., Whittam T. S. 2000. 

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radiation. J. Virol. 79: 14244-14252. 

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Control 24: 313-342. 

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WHO. www.who.int/csr/disease/avian_influenza/country/cases_table_2007_10_31/en/index.html (31 

October 2007). 

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Yarus M., Sinsheimer R. L. 1964. The UV-resistance of double-stranded Φ X174 DNA. J. 

mol. Biol. 8: 614-615. 

Závadova Z., Gresland L., Rosenbergová M. 1968. Inactivation of single-and doublestranded 

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APPENDIX I 

UVC (254 nm) radiation dose required for the inactivation of microorganisms and 

viruses (at room temperature, mWs cm -2 ) 

species 

VEGETATIVE BACTERIA 

inactivation - log10 units / 

% inactivation 

1 2 3 4 5 

90 99 99.9 99.99 99.999 


references 

Bacillus anthracis 4.5-28 8.7-42 8.7-56 12-70 15-84 3, 37, 39, 56 

Bacillus subtilis 3.7-12 7.4-18 11-14 15 18 

Escherichia coli 1.3-5.1 2.8-10 4.1-16 5.0-28 7.7-36 

3, 37, 39, 52, 

68, 87 

3, 4, 6, 8, 13, 

15, 22, 30, 31, 

34, 37, 39, 41, 

49, 58, 69, 70, 

73, 75, 76, 78, 

79, 80, 88, 91 

Klebsiella pneumoniae 15 11-31 29-39 49, 80, 91 

Mycobacterium tuberculosis 0.5-2.3 1.0-6.0 1.5-10 2.0-13 2.4-17 

Proteus mirabilis 0.9 1.8 2.7 3.6 4.5 34 

Pseudomonas aeruginosa 1.0-5.5 1.9-11 2.9 -17 3.9-22 4.8-28 

Salmonella sp. 1.8-5.0 3.2-7.0 5.4-9.0 7.1-25 8.3-15 

Staphylococcus aureus 1.9 -5.5 3.9-11 5.8-17 7.8-22 9.7-28 

Vibrio cholerae 0.8 1.4-6.5 2.2-12 5.0-21 19 

BACTERIAL SPORES 

Bacillus anthracis 74 149 223 297 371 42 

Bacillus anthracis 28 42 56 70 84 56 

Bacillus pumilus 20 55 

Bacillus subtilis 10-39 17-38 22-58 29-80 36-121 

YEASTS 

Candida albicans 7.6-12 11-17 15-22 18-27 22-32 60 

Cryptococcus neoformans, 

melanized 

34 68 102 136 170 84 

Cryptococcus neoformans, 

non-pigmented 

16 32 48 64 80 84 

3, 21, 38, 39, 

42 

3, 37, 39, 42, 

80 

3, 15, 37, 39, 

41, 49, 79, 80, 

88 

3, 15, 16, 37, 

39 

3, 37, 39, 64, 

79, 80 

3, 15, 22, 37, 

45, 53, 56, 59, 

61, 62, 68, 73- 

75

MOLD SPORES 

Aspergillus sp. 35-67 134 99-330 117-440 147-550 29, 37, 39, 42 

Aspergillus fumigatus 54 108 162 216 270 29 

VIRUSES 

Adenoviridae 27-49* 47 

Adenovirus 1 35 69 103 138 57 

Adenovirus 2 40-61 78-109 119-163 160 198 22, 23, 28, 42 

Adenovirus 5 216-240 305 38, 83 

Adenovirus 6 39 77 115 154 57 

Adenovirus 40 30 61 93 124 155 51 

Adenovirus 41 24 53 82 112 141 51 

Arenaviridae 3.5* 47 

Astroviridae 10-12* 47 

Bunyaviridae 2.0-3.5* 47 

Caliciviridae 9.7-11* 47 

Canine calicivirus 20 24 

Feline calicivirus 

4.8 12 19 24, 78 

Coronaviridae 0.7-1.1* 47 

SARS coronavirus 91 114-162 25, 40 

Berne virus 5 85 

Deltaviridae 22* 47 

Filoviridae 2.0* 47 

Flaviviridae 6.8-8.4* 47 

Hepadnaviridae 3.8-4.1* 47 

Herpesviridae 3.5-7.0* 47 

Epstein Barr virus 16 - 23 32 

Herpes simplex virus 1 3.7-10 7.4-20 11 24 37 32, 63, 86 

Herpes simplex virus 2 0.4 0.7 11 13 86 

Equine herpes virus 7.5 85 

Orthomyxoviridae 2.0-3.0* 47 

Influenza A 1.8 1.3-8.2 2.0 3.3 1, 12, 35 

Papovaviridae 68-103* 47 

Polyomavirus 47 43-94 141 44, 81 

Simian virus 40 105-300 130-261 440 551 


2, 9-11, 18, 26, 

38, 65, 66, 77

Paramyxoviridae 3.0* 47 

Parvoviridae 2.1-3.2* 47 

Parvovirus H-1, hamster 

osteolytic virus 

23 46 19 

Porcine parvovirus ca. 83 17 

Murine parvovirus

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