Proposed Registration Decision PRD2025-04, Putrescent whole egg solids, indole, sucrose, trimethylamine, Saccharomyces cerevisiae strain Y243, and related end-use products

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Pest Management Regulatory Agency
25 July 2025
ISSN: 1925-0886 (PDF version)
Catalogue number: H113-9/2025-4E-PDF (PDF version)

Summary

Table of contents

• Proposed registration decision for putrescent whole egg solids, indole, sucrose, trimethylamine, and Saccharomyces cerevisiae strain Y243
• What does Health Canada consider when making a registration decision?
• What are putrescent whole egg solids, indole, sucrose, trimethylamine, and Saccharomyces cerevisiae strain Y243?
• Health considerations
• Environmental considerations
• Value considerations
• Measures to minimize risk
• Next steps
• Other information

Proposed registration decision for putrescent whole egg solids, indole, sucrose, trimethylamine, and Saccharomyces cerevisiae strain Y243

Health Canada's Pest Management Regulatory Agency (PMRA), pursuant to subsection 28(1) of the Pest Control Products Act, is proposing registration for the sale and use of Rescue Egg Technical, Big Bag Indole Technical, Rescue Sucrose Technical, Rescue Trimethylamine Technical, Rescue Saccharomyces cerevisiae Technical, and related end-use products, Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap, containing the active ingredients putrescent whole egg solids, indole, sucrose, trimethylamine, and Saccharomyces cerevisiae strain Y243, to attract and trap flies in urban and rural residential and recreational areas.

Putrescent whole egg solids were first registered in Canada in 1983 for use as an animal repellent and a feeding deterrent on a variety of non-edible plants, trees and shrubs in nurseries, greenhouses, forestry plantations, and residential outdoor settings. All registered products containing putrescent whole egg solids were discontinued by the registrant in 2024.

An evaluation of available scientific information found that, under the approved conditions of use, the health and environmental risks and the value of the pest control products are acceptable.

This summary describes the key points of the evaluation, while the Science evaluation of Proposed Registration Decision PRD2025-04, Putrescent Whole Egg Solids, Indole, Sucrose, Trimethylamine, Saccharomyces cerevisiae strain Y243, and related end-use products provides detailed technical information on the human health, environmental and value assessments of putrescent whole egg solids, indole, sucrose, trimethylamine, S. cerevisiae strain Y243, and related fly trap end-use products.

What does Health Canada consider when making a registration decision?

The key objective of the Pest Control Products Act is to prevent unacceptable risks to individuals and the environment from the use of pest control products. Health or environmental risk is considered acceptable^{Footnote 1} if there is reasonable certainty that no harm to human health, future generations or the environment will result from use or exposure to the product under its proposed conditions of registration. The Act also requires that products have value^{Footnote 2} when used according to the label directions. Conditions of registration may include precautionary measures on the product label to further reduce risk.

To reach its decisions, Health Canada's PMRA applies modern, rigorous risk-assessment methods and policies. These methods consider the unique characteristics of sensitive subpopulations in humans (for example, children). They also consider the unique characteristics of organisms in the environment. These methods and policies also consider the nature of the effects observed and the uncertainties when predicting the impact of pesticides. For more information on how Health Canada's PMRA regulates pesticides, the assessment process and risk-reduction programs, please visit the Pesticides and pest management portion of Canada.ca.

Before making a final registration decision on putrescent whole egg solids, indole, sucrose, trimethylamine, S. cerevisiae strain Y243, and related fly trap end-use products, Health Canada's PMRA will consider any written comments received from the public in response to PRD2025-04^{Footnote 3}. Health Canada will then publish a Registration Decision^{Footnote 4} on putrescent whole egg solids, indole, sucrose, trimethylamine, S. cerevisiae strain Y243, and related fly trap end-use products, which will include the decision, the reasons for it, a summary of comments received on the proposed registration decision and Health Canada's response to these comments.

For more details on the information presented in this summary, please refer to the Science evaluation of PRD2025-04.

What are putrescent whole egg solids, indole, sucrose, trimethylamine, and Saccharomyces cerevisiae strain Y243?

Putrescent whole egg solids are a non-conventional product typically used as an animal repellent or a feeding deterrent to protect non-edible plants. In fly trapping products, putrescent whole egg solids are an attractant for pest fly ("filth fly") species, including house flies and blow flies.

Putrescent whole egg solids begin to decompose on contact with water and release airborne compounds that attract filth flies for egg-laying and feeding.

Indole is a non-conventional organic compound formulated as a white-yellow crystalline solid with a fecal odour that is used to attract flies.

Trimethylamine is a non-conventional organic compound formulated as a colorless gas with a fishlike odour that is used to attract flies.

Saccharomyces cerevisiae strain Y243 (baker's yeast) is a non-conventional product used as a fermentation agent, which releases airborne compounds to attract flies. The strain of S. cerevisiae used to produce strain Y243 is marketed as baker's yeast and is the same strain used to produce the food grade edible ingredient.

Sucrose (also referred to as table sugar or cane sugar) is a non-conventional product that feeds the yeast when used in a fermentation reaction process to attract flies.

Health considerations

Can approved uses of Putrescent Whole Egg Solids, Indole, Sucrose, Trimethylamine, and Saccharomyces cerevisiae strain Y243 affect human health?

Putrescent whole egg solids, indole, sucrose, trimethylamine, and S. cerevisiae strain Y243 are unlikely to affect human health when used according to label directions.

Potential exposure to putrescent whole egg solids, indole, sucrose, trimethylamine, and S. cerevisiae strain Y243 may occur when handling products, including the loading of reusable versions, or when standing close enough to inhale the fumes from the loaded traps, despite the unpleasant odour.

Toxicology studies in laboratory animals describe potential health effects from varying levels of exposure to a chemical and identify the dose where no effects are observed. When assessing health risks, two key factors are considered:

• the levels where no health effects occur and
• the levels to which people may be exposed.

The levels used to assess risks are established to protect the most sensitive human population (for example, children and nursing mothers). As such, sex and gender are taken into account in the risk assessment. Only uses for which the exposure is well below levels that cause no effects in animal testing are considered acceptable for registration.

Putrescent whole egg solids are of low toxicity but are considered potential sensitizers, and are known allergens.

Sucrose and S. cerevisiae strain Y243 (baker's yeast) have an extensive history of safe food use. However, microbial pest control agents (MPCAs) such as yeast are considered to be potential eye irritants and all MPCAs are considered to be potential sensitizers.

Publicly available toxicology information was assessed for trimethylamine and indole.

Trimethylamine is of high acute toxicity by the oral route of exposure and is of low acute toxicity by the inhalation route of exposure. It is extremely irritating or corrosive to eyes and skin. Animals given repeated high doses of trimethylamine in the diet showed decreases in body weight gain and food consumption, and increased tissue damage in the gastrointestinal tract. In pregnant animals, exposure to trimethylamine by the oral route of exposure showed no evidence of sensitivity of the young. Trimethylamine is not mutagenic or genotoxic.

Indole is of moderate acute toxicity by the oral and dermal routes of exposure. It is irritating to the respiratory tract, corrosive to eyes, non-irritating to skin, and is not a skin sensitizer. Animals given repeated high doses of indole in the diet exhibited decreases in body weight gain. Indole is not mutagenic or genotoxic. The levels of indole in the proposed fly trap end-use products are similar to those produced naturally in the human body.

The end-use products, Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap, contain a mixture of putrescent whole egg solids, indole, sucrose, trimethylamine, and S. cerevisiae strain Y243, which act as the insect attractant (bait). In laboratory animals, the fly trap bait was considered to be of low acute toxicity by the oral route of exposure. Published scientific literature and publicly available information for the active ingredients was used to inform the toxicology profile of the bait. Consequently the fly trap bait is considered to be of low acute toxicity by the oral route of exposure, corrosive to eyes and skin, and a potential sensitizer. The end-use product labels also require an egg allergen warning statement.

Residues in food and drinking water

Dietary risks from food and drinking water are acceptable.

The end-use products, Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap, are not proposed for food or feed uses. Dietary exposure, including drinking water, is not expected from the proposed use of putrescent whole egg solids, indole, sucrose, trimethylamine, and S. cerevisiae strain Y243 combined as an insect attractant (bait). Consequently, health risks from dietary exposure are acceptable for all segments of the population, including infants, children, adults, and seniors.

Risks in residential and other non-occupational environments

Estimated risk for residential and other non-occupational exposure is acceptable.

Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap are domestic class products proposed for outdoor use as insect traps on residential properties, including farms, and in areas of high fly activity, such as garbage and compost piles. Fly Trap and Big Bag Fly Trap are disposable traps, while Reusable Fly Trap, Fly Trap MAX, and POP! Fly Trap are reusable. All five traps contain bait pouches dissolved in water and can be disposed of in the garbage. Reusable traps can be manually emptied and re-loaded with a new water-soluble bait pouch.

The product labels will include measures to reduce user and bystander (including children and companion animals) exposure such as instructions to wear waterproof gloves when handling (including loading and emptying) the reusable fly traps, to keep the end-use products out of reach of children, and to hang traps in inaccessible areas. Furthermore, the traps should only be used outdoors in well-ventilated areas.

Residential and non-occupational exposure to Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap is expected to be low when label directions are observed. Consequently, the health risk to residents and the general public is acceptable.

Occupational risks from handling Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap

An occupational risk assessment was not required for Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap.

Since Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap are domestic class products, an occupational risk assessment was not required.

Environmental considerations

What happens when putrescent whole egg solids, indole, sucrose, trimethylamine, and Saccharomyces cerevisiae strain Y243 are introduced into the environment?

When used according to label directions, environmental risks associated with putrescent whole egg solids, indole, sucrose, trimethylamine, and S. cerevisiae strain Y243 and their fly trap end-use products are acceptable.

Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap, all containing the attractants putrescent whole egg solids, indole, sucrose, trimethylamine, and S. cerevisiae strain Y243, consist of a water-soluble pouch containing the attractants that is enclosed in a plastic bag or bottle. The traps are filled with water and hung outdoors near homes. The environmental releases from the traps are expected to be minimal. Therefore, the environmental risks associated with these fly trap products are acceptable when they are used according to label directions.

Value considerations

What is the value of Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap?

These five related fly trap products can be used to attract, trap, and subsequently reduce populations of filth fly species, which are potential disease vectors for humans and livestock.

The registration of Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap will provide Canadians with a non-conventional method of reducing filth flies in urban and rural residential and recreational areas compared to sprays or baits with conventional insecticides. Due to the non-conventional mode of action of these products, resistance is very unlikely to occur; therefore, these products may aid in reducing insecticide resistance in fly populations.

Measures to minimize risk

Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human and environmental health. These directions must be followed by law.

The key risk-reduction measures being proposed on the labels of Rescue Egg Technical, Big Bag Indole Technical, Rescue Sucrose Technical, Rescue Trimethylamine Technical, Rescue Saccharomyces cerevisiae Technical, Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap to address the potential risks identified in this assessment are as follows.

Key risk-reduction measures - Human health

The following hazard statements are required on the technical grade active ingredient labels:

• "POTENTIAL SENSITIZER" and "Warning, contains the allergen egg" on Rescue Egg Technical;
• "DANGER – CORROSIVE TO EYES" and "POISON" on Big Bag Indole Technical;
• "DANGER POISON" and "CORROSIVE TO EYES and SKIN" on Rescue Trimethylamine Technical; and
• "CAUTION - EYE IRRITANT" and "POTENTIAL SENSITIZER" on Rescue Saccharomyces cerevisiae Technical.

Additionally, standard hazard and precautionary statements are required on the technical grade active ingredient labels.

The following hazard statements are required on the end-use product labels: "DANGER - CORROSIVE TO EYES and SKIN", "POTENTIAL SENSITIZER", and "Warning, contains the allergen egg". Standard precautionary statements are also required on the end-use product labels to inform users that products are corrosive to the eyes and skin, to not apply if allergic to eggs, and to warn of the potential for sensitization and irritation to the respiratory tract.

Domestic users handling the reusable traps (Reusable Fly Trap, Fly Trap MAX, and POP! Fly Trap) will be required to wear waterproof gloves when handling (including loading and emptying) the fly traps.

Relevant standard label requirements apply to products with water-soluble packaging to mitigate user exposure.

To limit bystander exposure, the end-use product labels require the precautionary statements "Keep out of reach of children and pets" and "Only use traps outdoors in well-ventilated areas".

Key risk-reduction measures - Environment

Label statements ensuring disposal in household garbage are required.

Next steps

Before making a final registration decision on putrescent whole egg solids, indole, sucrose, trimethylamine, S. cerevisiae strain Y243, and related end-use products, Reusable Fly Trap, Fly Trap, Fly Trap MAX, POP! Fly Trap, and Big Bag Fly Trap, Health Canada's PMRA will consider any written comments received from the public in response to PRD2025-04 up to 45 days from the date of publication (25 July 2025) of PRD2025-04. Please forward all comments to PMRA Publications, through the Public Engagement Portal (Public Engagement Forms – Consultation Comment).

Health Canada will then publish a Registration Decision, which will include its decision, the reasons for it, a summary of comments received on the proposed decision and Health Canada's response to these comments.

Other information

When Health Canada's PMRA makes its registration decision, it will publish a Registration Decision on putrescent whole egg solids, indole, sucrose, trimethylamine, S. cerevisiae strain Y243, and related fly trap end-use products (based on the Science evaluation section of PRD2025-04). In addition, the test data referenced in this consultation document will be available for public inspection, upon application, in the PMRA's Reading Room. For more information or if you have questions, please contact the PMRA's Pest Management Information Service.