1-chloro-1,1-difluoroethane

Toxicity to microorganisms

Administrative data

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP non-guideline experimental study, published in peer reviewed literature, notable limitations in design and/or reporting

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

Effect of gas hydrate formers on microorganisms

Author:

Prior BA, Fennema O and Marth EH

Year:

1970

Bibliographic source:

Applied Microbiology, Vol. 20, No. 1, p. 139-144

Materials and methods

Principles of method if other than guideline:

Three concentrations of 1-chloro-1,1-difluoroethane tested on various bacteria. Changes in numbers of microorganisms determined by plate count after 48 hours exposure.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

1-chloro-1,1-difluoroethane

EC Number:

200-891-8

EC Name:

1-chloro-1,1-difluoroethane

Cas Number:

75-68-3

Molecular formula:

C2H3ClF2

IUPAC Name:

1-chloro-1,1-difluoroethane

Details on test material:

1-chloro-1,1-difluoroethane (CH3CClF2)
fluorocarbon-142b, Allied Chemical Corp.
purity 98%

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
None

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

Not applicable

Test solutions

Vehicle:

no

Details on test solutions:

1-chloro-1,1-difluoroethane was tested in the vapor state (vapor space was saturated at 21°C, but the amount was insufficient to cause condensation). 1-chloro-1,1-difluoroethane, iin a partially liquefied state, was further tested at two levels: (i) sufficient 1-chloro-1,1-difluoroethane was present at 21 °C to saturate the vapor space and to provide a few drops of liquid condensate in the culture medium, and (ii) sufficient 1-chloro-1,1-difluoroethane was present at 21 °C to saturate the vapor space and to provide liquid in an amount theoreticlaly adequate to bind all water present.

The buret used for dispensing liquid or vapor-state 1-chloro-1,1-difluoroethane into aerosol cans was similar to those available commercially, except that a membrane filter (0.22 µm pore size; Millipore Corp., Bedford, Mass.) was inserted between the buret and the aerosol cans.

Test organisms

Test organisms (species):

other: various bacteria

Details on inoculum:

The bacteria chosen represent a broad cross-section of those common in foods. Organisms except bacterial sporeformers were prepared by growing them in sterile AC Broth (Difco) at their respective optimum temperatutes. Sterile AC Broth (Difco) was employed as the culture medium for all organisms during incubation in aerosol cans.

The following microorganisms were tested:
Staphylococcus aureus
Micrococcus conglomeratus
Streptococcus cremoris
S. lactis
Leuconostoc citrovoru"n
Leuconostoc dextranicum
Bacíllus cereus (spores)
B. polymyxa (spores)
Escherichia coli
E. íntermedia
Salmonella typhímuríum
Pseudomonas aeruginosa
Pseudomonas fluorescens
Pseudomonas fragi
Achromobacter butyri
Flavobacterium devorans
Saccharomyces cerevisiae
Candida utilis

Study design

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Remarks on exposure duration:

1 - 48 h

Post exposure observation period:

No data

Test conditions

Hardness:

No data

Test temperature:

21 ± 3 °C

pH:

No data

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

1.68 - 1.99 - 7.92 g.
The amount of 1-chloro-1,1-difluoroethane was determined by weighing each can before and after filling

Details on test conditions:

1-chloro-1,1-difluoroethane was added aseptically to capped aerosol cans (200x214, 143 mL capacity) containing 20 ml of sterile broth and a 24-hr culture of the test microorganism. Controls devoid of 1-chloro-1,1-difluoroethane were included with each treatment. Test samples were prepared in triplicate and control samples in duplicate. Avoidance of contamination during filling and sealing of the aerosol cans was verified by using uninoculated controls. Samples were incubated while being agitated continuously an a platform shaker. The numbers of bacteria were determined by plate count (Plate Count Agar (Difco)) both prior to and after incubation.

Reference substance (positive control):

yes

Remarks:

not specified in the publication

Results and discussion

Results with reference substance (positive control):

No data

Reported statistics and error estimates:

The resistance of the various microorganisms to the vapor-state of the test substance was compared statistically with microbial characteristics such as Gram reaction, sporulation, capsulation, shape, surface-to-volume ratios, and optimum termperature growth as reported in Bergey's Manual. Significant correlations were lacking in all instances.

Any other information on results incl. tables

Results Vapor Phase

	Fractional change in numbers after 48 hr [(no./ml (treated)/no./ml (control)]
Microorganism	No initial	No 48h
Staphylococcus aureus	4.1	16
Micrococcus conglomeratus	0.15	4.7 x 10 ^ -5
Streptococcus cremoris	1.1	1.8 x 10 ^ -2
S. lactis	110	0.13
Leuconostoc citrovorum	0.61 x 10 ^ -2	1 x 10 ^ -3
Leuconostoc dextranicum	7.8	0.52
Bacillus cereus (spores)	1.3 x 10 -2	0.35
B. polymyxa (spores)	0.65	0.5 x 10 ^ -1
Escherichia coli	0.27	3.5 x 10 ^ -3
E. intermedia	0.15	1 x 10 ^ -4
Salmonella typhimurium	30.8	1.8
Pseudomonas aeruginosa	5.2 x 10 ^ 2	1.1
Pseudomonas fluorescens	73	9.2 x 10 ^-2
Pseudomonas fragi	6.3	5.6 x 10 ^-4
Achromobacter butyri	1.0 x 10 ^-3	9.0 x 10 ^-6
Flavobacterium devorans	1.3	6.3 x 10 ^-4
Saccharomyces cerevisiae	57	0.57
Candida utilis	12	5.1 x 10 ^-2

Results Liquid Phase

	Fractional change in numbers after 48 hr [(no./ml (treated)/no./ml (control)]
	Low level of liquid		High level of liquid
Microorganism	No initial	No 48h	No initial	No 48h
Escherichia coli	NO*	NO	3.6 x 10 ^-6	1.1 x 10 ^ -6
Pseudomonas fluorescens	1.9 x 10 ^-7	3.6 x 10 ^ -9	NO	NO
P. aeruginosa	NO	NO	NO	NO
Leuconostoc dextranicum	8.8 x 10 ^-4	6.7 x 10 ^-6	1.4 x 10 ^-4	1.1 x 10 ^-6
Saccharomyces cerevisiae	NO	NO	NO	NO
Streptococcus lactis	NO	NO	NO	NO
Salmonella typhimurium	3.3 x 10 ^-5	2.5 x 10 ^-6	6.7 x 10 ^-7	5.0 x 10 ^-8
Staphylococcus aureus	1.9 x 10 ^-4	1.4 x 10 ^-4	NO	NO
Bacillus cereus (spores)	4.1 x 10 ^-3	41	8.6 x 10 -3	86

* NO=no viable organisms

Treatment with liquid 1-chloro-1,1-difluoroethane for 48 hours substantially reduced the number of viable organisms in all of the test cultures; however, the population of B. cereus in the treated samples decreased less than in the 48 hr control. All cultures except B. cereus were reduced to less than 10,000 organisms per ml after 48 hours in the presecen of liquid 1-chloro-1,1-difluoroethane.

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

Treatment with liquid 1-chloro-1,1-difluoroethane for 48 hours substantially reduced the number of viable organisms in all of the test cultures; however, the population of B. cereus in the treated samples decreased less than in the 48 hr control. All cultures except B. cereus were reduced to less than 10,000 organisms per ml after 48 hours in the presecen of liquid 1-chloro-1,1-difluoroethane.

Executive summary:

Three concentrations of 1-chloro-1,1-difluoroethane tested on various bacteria. Changes in numbers of microorganisms determined by plate count after 48 hours exposure. The resistance of the various microorganisms to the vapor-state of the test substance was compared statistically with microbial characteristics such as Gram reaction, sporulation, capsulation, shape, surface-to-volume ratios, and optimum termperature growth as reported in Bergey's Manual. Significant correlations were lacking in all instances.Treatment with liquid 1-chloro-1,1-difluoroethane for 48 hours substantially reduced the number of viable organisms in all of the test cultures; however, the population of B. cereus in the treated samples decreased less than in the 48 hr control. All cultures except B. cereus were reduced to less than 10,000 organisms per ml after 48 hours in the presecen of liquid 1-chloro-1,1-difluoroethane.