Ethyl formate

Toxicity to microorganisms

Description of key information

Toxicity to microorganism:

The toxicity study was carried out to test the effects of test material in Colletotrichum musae DAR 24962. The MIC of each of the substance was evaluated and compound was classified as germicidal or germistatic in its effect on decay microorganisms. A germicidal effect is the death of a microorganism, whereas a germ static effect is the inhibition of microbial replication). The agar disks of decay microorganisms which failed to grow due to the MIC of the compound were transferred onto new agar media free from the tested volatile and incubated for a further 5 days at 25 °C. The test material exhibited germicidal activity. The MIC was found to be 551.89mg/l

Key value for chemical safety assessment

EC50 for microorganisms:

551 mg/L

Additional information

Toxicity to microorganism:

Short-term toxicity of the test compound to aquatic microorganism were reviewed from reliable sources. The summary of the results are presented below: 

 

The acute toxicity of test material to Colletotrichum musae was assessed during a 10 days static test (In Vitro Efficacy of Plant Volatiles for Inhibiting the Growth of Fruit and Vegetable Decay Microorganisms, 2002). The static toxicity test was conducted for 5 days at 25°C. The method for cultivation used as the surface-plated cultures of the decay fungi in plastic Petri dishes were sub-cultured by streaking the spores onto the new potato dextrose agar (PDA) media. .The new plated cultures were then incubated for 7 days at 25 °C. The spores of 7-day-old cultures of decay fungi was dislodged by sterile distilled water to which 0.1 mL/L of Tween 80 had been added. The spores was then filtered with sterile Sinta Glass No. 1 to remove debris such as mycelia and the aliquot was diluted to a concentration of 105 fungal spores/mL suspensions .The fungal spore 0.1 mL was then dispensed into Petri dishes (9-cm diam.) containing agar medium (PDA). The Petri dishes were then incubated for 3 days for the fungal cultures at 25 °C, to allow the spores to grow. Agar plugs (5.5-mm diam.) were picked up from the 3-day-old cultures of decay fungi using the bottom end of a sterilized Pasteur pipette and then transferred onto the centers of new PDA Media in 9-cm plastic Petri dishes. The Petri dishes were then inverted and 7-cm Whatman No. 1 filter papers were attached on to the inner surface of their lids. Ethanol, the first tested volatile in this experiment, was impregnated into the filter paper with varying volumes from 0.1 to 1.0 mL/dish in the 4 °C room. Immediately after the impregnation, the Petri dishes were sealed bywrapping them with plastic film (Vitafilm, Goodyear, Sydney) and incubated for 10 days at 25 °C. Experiments were repeated two times with four replications for each experiment. The minimum concentration of ethanol (expressed as mmol/dish) required to give complete control or the minimum inhibitory concentration (MIC) for each microorganismwas determined. The MIC of ethanol for each target decay microorganism was used as the initial level to identify the MIC of other tested volatiles. If the MIC level of ethanol used for other volatiles failed to stop the growth of pathogen, the level was increased until the MIC was found. However, if the volume of 1.5 mL/dish still failed to stop the growth of pathogen, the compound was considered ineffective as a vapor to stop the growth of pathogens. When the tested compounds had the same effect as the MIC of ethanol, the concentration was decreased until the MIC of the compound for each microorganism was determined.

The MIC of each of the substance was evaluated and compound was classified as germicidal or germistatic in its effect on decay microorganisms. A germicidal effect is the death of a microorganism, whereas a germ static effect is the inhibition of microbial replication). The agar disks of decay microorganisms which failed to grow due to the MIC of the compound were transferred onto new agar media free from the tested volatile and incubated for a further 5 days at 25 °C. The test material exhibited germicidal activity. The MIC was found to be 551.89mg/l

 

Short term aquatic toxic effects of the test compound was assessed on Erwinia carotovora. The in-vitro study aimed to evaluate the effectiveness of test material as an antimicrobial agent against several major fruit and vegetable decay microorganisms (bacteria). The bacteria, were obtained in the form of lyophilized cultures, were mixed with nutrient broth and the mixture was then streaked onto nutrient Agar (NA) media. The new plated cultures were then incubated for 7 days at 25 °C. The cells of 7-day-old cultures of decay bacteria were dislodged by sterile distilled water to which 0.1 mL/L of Tween 80 had been added. The cell suspensions were then filtered with sterile Sinta Glass No. 1 (Gallenkamp, London) to remove debris such as condensed agar fragments, and the aliquot was diluted to a concentration of 10E5 Bacterial cells/mL suspensions.

The bacterial cell suspensions, 0.1 mL was then dispensed into Petri dishes (9-cm diam.) containing agar medium NA. The Petri dishes were then incubated for 5 days for the bacterial cultures, both at 25 °C, to allow the cells to grow. The study is conducted on static condition for 10 days for post exposure observation period included 5 days at 25°C. This gram negative bacteria showed germicidal effect at minimum concentration of 6.52 mmol/dish. The minimum inhibitory concentration MIC was found to be 483mg/L (conversion of 6.52 mmol into mg/L).

 

The toxicity to microorganisms of test material to Pseudomonas aeruginosa was assessed during a 10days static test. The MIC of each of the volatiles was evaluated and compound was classified as germicidal or germistatic in its effect on decay microorganisms. A germicidal effect is the death of a microorganism, whereas a germistatic effect is the inhibition of microbial replication). The agar disks of decay microorganisms which failed to grow due to the MIC of the compound were transferred onto new agar media free from the tested volatile and incubated for a further 5 days at 25 °C.The toxicity study was performed on microorganism (bacteria) Pseudomonas aeruginosa DAR 25580 to assess the effects of ethyl formate. The gram negative bacteria show germicidal effect at minimum concentration of 6.21 mmol/dish. Therefore MIC was found to be 460.03mg/l (conversion of 6.21 mmol into mg/L) for test material in bacteria.

 The toxicity to microorganisms of test material to Rhizopus stolonifer was assessed during a 10 days static test. The toxicity study was carried out to assess the effects of test material on Rhizopus stolonifer DAR 43352 The MIC of each of the volatiles was evaluated and compound was classified as germicidal or germistatic in its effect on decay microorganisms. A germicidal effect is the death of a microorganism, whereas a germ static effect is the inhibition of microbial replication). The agar disks of decay microorganisms which failed to grow due to the MIC of the compound were transferred onto new agar media free from the tested volatile and incubated for a further 5 days at 25 °C. The Ethyl formate exhibited germicidal activity as MIC was found to be 851.17mg/l.

 

Based on the studies summarized in the above reports for the target substance . The endpoint value was found to vary between Minimum Inhibitory Concentration (MIC) = 851.17 to 460.03 in a 10 days study. Based on the studied values, it is concluded that test material does to exhibit short term toxicity to microorganism i.e. it is non hazardous to the aquatic environment.