This is a joint FSA and FSS publication.

1. Introduction

The FSA and FSS have undertaken an assessment of a feed additive submitted by Lallemand Animal Nutrition UK Ltd. (Spring Lane North, Malvern link, Worcestershire, WR14 1BU, UK) consisting of Saccharomyces cerevisiae CNCM I-1079 under assimilated Regulation (EC) No 1831/2003 (EC, 2003) in each nation of Great Britain (GB). The applicant seeks authorisation for a new use in feed for dogs and all other Canidae, under the category ‘zootechnical additives’, functional group ‘gut flora stabilisers’.

In line with Article 8 of assimilated Regulation No 1831/2003 (EC, 2003), the assessment has considered and concluded whether the feed additive complies with the conditions laid down in Article 5, including: safety considerations for human, animal and environmental health; efficacy of the additive for its intended effect; potential impairment of the distinctive features of animal products. This, and the guidance put in place by the European Food Safety Authority (EFSA) for the evaluation of feed additive applications, has formed the basis and structure for the assessment.

To ensure the regulatory systems of FSA/FSS are risk proportionate, and resources are used effectively, the FSA and FSS have used the evidence submitted by the applicant and other information in the public domain, including the EFSA risk assessment opinion, to provide a summary assessment of the evidence of safety presented in this report.

In 2016, EFSA published a risk assessment opinion on the safety and efficacy of a feed additive containing S. cerevisiae CNCM I-1079 when used as a zootechnical additive in feed for weaned piglets and sows (EFSA FEEDAP Panel, 2016). Following the 2016 opinion, EFSA published a risk assessment in 2019 on the safety and efficacy of S. cerevisiae CNCM I-1079 as a feed additive for turkeys for fattening (EFSA FEEDAP Panel, 2019b). These opinions were published when the UK was still part of the EU, therefore the conclusions are considered applicable to GB.

In 2024 EFSA published a risk assessment opinion on the safety and efficacy of an additive containing S. cerevisiae CNCM I-1079 for use in all dogs and other Canidae (EFSA FEEDAP Panel, 2024), but the Panel were unable to conclude on efficacy in dogs and other Canidae. This opinion has been reviewed by FSA/FSS risk assessors.

In 2025, following EFSA’s assessment of S. cerevisiae CNCM I-1079, the FSA was provided with the published study of the efficacy trial in dogs and a detailed rationale outlining why some of the endpoints not reported in the EFSA opinion were considered relevant to dogs. The FSA asked the Advisory Committee on Animal Feedingstuffs (ACAF) for advice on the efficacy data provided. Based on the efficacy trial and the additional information provided, the ACAF advised that S. cerevisiae CNCM I-1079 has the potential to be efficacious in dogs and all other Canidae under the proposed conditions of use. The result of EFSA’s assessment combined with the advice from the ACAF has provided sufficient evidence of safety and efficacy for the FSA and FSS to conclude on the additive’s safety and efficacy at this time. This assessment represents the opinion of the FSA and FSS.

Table 1.Table showing products included in this assessment
Title Product type Intended use/⁠s Intended dose/⁠intake
Saccharomyces cerevisiae CNCM I-1079 Feed additive Zootechnical additive/gut flora stabiliser Minimum content of 1 x 109 CFU/kg

2. Assessment

2.1. Details of other regulators opinions

2.1.1. Current authorisation

S. cerevisiae CNCM I-1079 is currently authorised as a zootechnical feed additive in GB and EU (4d1703) for use in the following animal categories:

  • Sows and weaned piglets, under assimilated EU Regulation 2018/347 and Commission Implementing Regulation (EU) No 2018/347 (EC, 2018).

  • All pigs other than sows and weaned piglets, and all minor porcine species, under assimilated EU Regulation 2019/892 and Commission Implementing Regulation (EU) No 2019/892 (EC, 2019).

  • Chickens for fattening and minor poultry species for fattening, under assimilated EU Regulation 2017/1905 and Commission Implementing Regulation (EU) 2017/1905 (EC, 2017).

  • Turkeys for fattening, under assimilated EU Regulation 2020/162 and Commission Implementing Regulation (EU) 2020/162 (EC, 2020).

The additive is authorised in all pigs in the same functional group that is requested in the current application (gut flora stabilisers), but is authorised in chickens, minor poultry species and turkeys for fattening in the functional group “other zootechnical additives”, specifically for reducing carcass contamination with Salmonella spp.

In 2024, EFSA released a scientific opinion on the safety and efficacy of S. cerevisiae CNCM I-1079 for use in dogs and all other Canidae. However, they were unable to conclude on the efficacy of the additive under the proposed conditions of use. The additive is not authorised in the EU or GB for use in dogs and other Canidae.

2.1.2. Other regulators opinions

In 2016, the EFSA published a scientific opinion on the safety and efficacy of an additive containing S. cerevisiae CNCM I-1079 when used as a zootechnical additive in feed for weaned piglets and sows (EFSA FEEDAP Panel, 2016). The identity of the additive and the active agent was demonstrated, and the active agent is suitable for the EFSA QPS approach and safe for the target species, consumers and the environment. The additive has the potential to be efficacious in sows when used at a dose of 1 x 109 CFU/kg feed.

In 2019, the EFSA published a scientific opinion on the safety and efficacy of S. cerevisiae CNCM I-1079 as a feed additive for turkeys for fattening (EFSA FEEDAP Panel, 2019b). The Panel evaluated new data provided relating to the physical-chemical properties of the additive and no concerns were raised.

In 2024, the EFSA published a risk assessment on the safety and efficacy of an additive containing S. cerevisiae CNCM I-1079 for use in all dogs and other Canidae (EFSA FEEDAP Panel, 2024). The Panel reiterated their conclusion that the active agent is suitable for the QPS approach and safe for the target species, consumers and the environment. The additive is considered a skin and respiratory sensitiser, and a potential eye irritant. The non-coated form of the additive is non-irritating to skin and eyes, but no conclusion could be made regarding the eye irritation potential of the coated formulation. No conclusion could be made on efficacy of the additive for dogs and other Canidae.

These opinions have been reviewed by FSA/FSS risk assessors. It has been verified that the standard approach, when compared to the relevant guidance applied in GB, has been followed and the conclusions made are consistent with the data summarised in the opinion.

2.1.3. Methodology applied in the EFSA opinion

The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) assessed the safety and the efficacy of the additive, in accordance with the following guidance documents:

and principles in Assimilated Regulation (EC) No 429/2008.

These guidance documents also apply to the assessment framework of applications submitted to the FSA for authorisation.

2.2. Section II: Identity, characterisation and condition of use

2.2.1. Characterisation of the active agent

S. cerevisiae CNCM I-1079 was originally isolated from grape must and has not been genetically modified. The strain has been deposited with the Collection Nationale de Cultures de Microorganismes (CNCM), under the accession number I-1079.

The taxonomic identity of the strain as S. cerevisiae was confirmed, based on whole-genome sequence (WGS) analysis against other Saccharomyces spp. Using a read-mapping approach, the highest alignment was found to be to the reference genome S. cerevisiae S288C. Additionally, the applicant provided taxonomic analysis via internal transcribed spacer analysis; the closest match was the type-strain S. cerevisiae NRRL Y-12632T (CBS 1171).

2.2.2. Characterisation of the additive

There are two formulations of the additive, both containing the active agent:

  • A non-coated formulation (minimum 2 x 1010 CFU/g)

  • A coated or microencapsulated formulation (minimum 1 x 1010 CFU/g)

The non-coated form has the appearance of brown/beige granular particles. The coated form includes vegetable oil fatty acids as coating agents (40%–50%), with the appearance of glossy beige/brown beadlets.

Batch-to-batch variation data were provided for 5 batches of each form of the additive; all batches exceeded the minimum specification. Mean cell counts for each formulation were as follows:

  • Non coated formulation: 3.5 x 1010 CFU/g (3 x 1010 to 4 x 1010 CFU/g)

  • Coated formulation: 1.6 x 1010 CFU/g (1.5 x 1010 to 1.6 x 1010 CFU/g)

The composition and the manufacturing process were reviewed in by the Panel in the 2016 opinion, and no concerns were identified (EFSA FEEDAP Panel, 2016). Data reviewed in previous opinions (EFSA FEEDAP Panel, 2016, 2017d, 2019b, 2019c, 2022) relating to composition, purity, physical-chemical properties and shelf-life were considered valid in the 2024 opinion.

Data on microbiological impurities were provided for three batches of each form of the additive. All results were within the specifications set by the applicant (<10 CFU/g Escherichia coli; Salmonella spp. absent in 25g; <1000 CFU/g Enterobacteriaceae and coliforms). The FEEDAP Panel agreed that the observed levels of microbial impurities did not raise safety concerns.

Data on dusting potential showed that the coated form did not produce any dust, and the non-coated form had a dusting potential ranging from 300 to 600 mg/m3 air. Particle size distribution (PSD) was evaluated in the 2019 EFSA FEEDAP opinion. PSD was determined using a molecular sieve method and found that 99.7% of particles were >45 µm for the non-coated form, and 100% of particles were >355 µm for the coated form (EFSA FEEDAP Panel, 2019b).

In the 2024 opinion, the stability of both forms of the additive in three batches of cold-extruded complementary dog feed (dog chews) was evaluated (EFSA FEEDAP Panel, 2024). The maximum temperature reached during processing was 50 °C. The additive was added prior to extrusion, and viable cell counts of the active agent were measured both prior to extrusion and during the storage period after extrusion. Analysed cell counts prior to extrusion ranged from 1.8 x 1011 to 1.4 x 1012 CFU/kg feed. Cell counts after storage at 20-25 °C in high-density polyethylene plastic jars at ambient humidity were within 0.5 log10 of initial cell counts after 6 months (coated form) and 24 months (non-coated form) for all three batches, which the FEEDAP Panel consider to be a negligible loss. 10 sub-samples of the feed were analysed to determine the capacity for homogeneous distribution in the feed. The coefficient of variation (CV) was 14.4% and 18.9% for the coated and non-coated form, respectively.

The FSA and FSS agree with the conclusions reached for the characterisation of the additive and the active agent. The taxonomic identification of the active agent as S. cerevisiae has been confirmed, and the amounts of the detected impurities do not raise safety concerns. The certificates of analysis were reviewed by the FSA and FSS and confirmed compliance with the specifications.

Based on the stability data provided, the FSA/FSS conclude that S. cerevisiae CNCM I-1079 is stable for processing at temperatures up to 50 °C, and stable in cold-extruded dog feed at room temperature for 6 months and 24 months for the coated and non-coated forms, respectively. The FSA/FSS note that 50 °C is below the temperature typically used during the processing of pet feed and therefore recommend that the stability to heat treatment is stated in the directions for use of the feed additive as a condition of any potential authorisation. The FSA/FSS note that the CV for both formulations is relatively high. However, the data were not log-transformed, and these CVs are within the expected range for untransformed homogeneity data for microbial additives. The FSA/FSS therefore conclude that both formulations of the additive are capable of homogenous distribution in feed.

2.2.3. Conditions of use

The additive is intended to be added to all types of feed for dogs and other Canidae, at a minimum use level of 1 x 109 CFU per kg complete feed. It is not intended for use in water.

The FSA/FSS agree with the conditions of use as proposed by the applicant but recommend that stability to heat treatment is stated in the directions for use of the feed additive as a condition of any potential authorisation.

2.2.4. Conclusion on Section II: Identity, characterisation and conditions of use

The FEEDAP Panel concluded that the active agent and both forms of the additive were fully characterised, and the amounts of the detected impurities do not raise safety concerns. Information on the stability and homogeneity in complementary dog feed was provided.

The FSA/FSS conclude that S. cerevisiae CNCM I-1079 is stable for processing at temperatures up to 50 °C, and stable in feed for 6 months and 24 months for the coated and non-coated forms, respectively. Both forms of the additive are capable of homogenous distribution in feed. The FSA/FSS agree with the conditions of use as proposed by the applicant but recommend that stability to heat treatment is stated in the directions for use of the feed additive as a condition of any potential authorisation.

2.3. Section III: Safety

2.3.1. Safety for the target species, consumers and the environment

The active agent is confirmed as suitable for the EFSA QPS approach and none of the other components of the additive pose a risk to the target species; therefore, the FEEDAP Panel concluded that the additive is safe for the target species. The additive is not intended to be used in food-producing animals; therefore, in line with technical guidance, an assessment of safety for consumers and the environment is not required.

2.3.2 Safety for the user

The non-coated form of the additive has a maximum analysed dusting potential of 600 mg/m3 air; therefore, the FEEDAP Panel concluded that exposure by inhalation is possible. Conversely, the coated form did not produce dust, so the FEEDAP Panel concluded that exposure by inhalation is unlikely. As a microbial additive, the additive is considered a respiratory sensitiser, and any exposure is considered a risk.

The skin and eye irritation potential of the non-coated form of the additive was assessed using in vivo studies conducted in accordance with OECD test guideline 404 and OECD test guideline 405, respectively. Based on the results of the studies, the FEEDAP panel concluded that the non-coated form is non-irritating to skin and eyes. No data were provided for the eye irritation potential of the coated form; therefore, in the absence of data the Panel were unable to conclude on the eye irritation potential of the coated form.

A skin sensitisation study conducted in accordance with OECD test guideline 429 was provided for the non-coated form. However, the FEEDAP panel were unable to conclude on skin sensitisation potential based on this study, as the OECD test guideline is not validated for use with microorganisms. The FEEDAP Panel therefore concluded that both forms of the additive are skin and respiratory sensitisers, and that any level of dermal or respiratory exposure is a risk.

FSA and FSS agree with the conclusions reached on the safety for the user.

2.3.3. Conclusion on Section III: Safety

The FEEDAP Panel concluded that both forms of the additive should be considered skin and respiratory sensitisers, and that any level of exposure is considered a risk. The non-coated form is not a skin or eye irritant, but the Panel could not conclude on the eye irritation potential of the coated form.

The FSA and FSS agree that the additive can be considered safe for the target species, consumer and the environment without the need for further studies. The FSA/FSS note that the coating agent used in the coated form is an authorised feed material in GB. The FSA/FSS agree with the user safety conclusions and agree that both forms of the additive should be considered skin and respiratory sensitisers, with any level of exposure considered a risk. The non-coated form is not a skin or eye irritant, but in the absence of data the coated form is considered a presumed eye irritant.

2.4. Section IV: Efficacy

The applicant submitted a single long-term trial evaluating the effect of supplementation with S. cerevisiae CNCM I-1079 on zootechnical performance of dogs (Canis familiaris) and their puppies. In 2024, the FEEDAP Panel were unable to conclude on efficacy in dogs and other Canidae as the Panel consider that effects on growth parameters are only evidence of efficacy when related to the health of the animals, for example, a subsequent improvement in morbidity or mortality.

In 2025, the applicant provided the FSA/FSS with additional information on efficacy, including the peer-reviewed journal article for the submitted study in dogs, which had been recently published (Garrigues, et al., 2024), in addition to a detailed rationale outlining why some of the endpoints not reported in the EFSA opinion were of important relevance to dog breeders. The FSA/FSS requested advice from the ACAF to evaluate the efficacy trial in dogs and the additional information submitted by the applicant.

The additive is authorised for use in all pigs (including sows) in GB at an inclusion rate of 1 x 109 CFU/kg feed, and therefore efficacy has already been demonstrated in this animal category. The applicant reasoned that a single study in dogs was sufficient, on the grounds that the observed benefits in sows and piglets are predicted to also occur in bitches and puppies, due to similarities between the two species. For example, sows and bitches both produce multiple offspring at a time, and both experience a stressful periparturient period. The ACAF agreed that the effects observed in the studies in sows were biologically relevant to dogs. Because the intended effect is the same, a single study in dogs was deemed acceptable.

The study in dogs and their puppies compared a control group with a treatment group, in which the basal feed of the bitches during gestation and lactation was supplemented with an intended dose of 1 x 109 CFU/kg complete feed. The health of bitches was monitored daily throughout the study, and mortality in the puppies was recorded. Zootechnical performance parameters were measured in both the bitches and the litters. A number of other endpoints were monitored during the study, some of which were not considered relevant by the ACAF. The ACAF raised concerns that the experimental design of the study was not optimal but agreed that the study could be considered suitable for assessment.

There were no differences between adult bitches in the control and treatment group for gestation or lactation duration, feed intake, body weight or Body Condition Score (p>0.1). However, there was an increase in faecal immunoglobulin A (IgA) between the end of gestation and the end of lactation for the treatment group, relative to the control (p<0.1). Additionally, faecal dry matter (DM) content was more stable in the treatment group, as evidenced by a decline in faecal DM in the control group, relative to the treatment group (p<0.1). The ACAF discussed the utility of faecal IgA as a biomarker of gut health, noting that although it may indicate an improved immune state, it can also be a result of other effects, such as an inflammatory response, for example. However, the ACAF agreed that the increase in faecal IgA could be considered as potential evidence of a beneficial effect of the additive in the adult dogs.

With regards to the effects on the litter, no differences were observed between treatment groups relating to the total number of puppies born, litter feed intake or pre-weaning mortality (p>0.1). There was a significant reduction in the number of low birthweight puppies, an improvement in growth rate homogeneity and increase in litter initial weight in the treatment group relative to the control (p<0.1). However, the increase in litter weight did not persist at weaning.

The ACAF noted that the published journal article (Garrigues, et al., 2024) included some endpoints that were not mentioned in the original trial report but were relevant to efficacy, including significant beneficial effects of the additive on the colostrum and milk composition of the bitches. These included an increase in the gross energy of the colostrum, and an increase in the protein concentration of the milk in the treatment group (p<0.05). The ACAF also accepted the applicant’s rationale that some of the differences seen in the treatment group (relative to the control) are particularly valuable to dog breeders. These include the observed improvement in the growth rate homogeneity of the litter, and the reduction in the risk of low birthweight puppies.

Considering all the evidence, the ACAF agreed that the additive has the potential to be efficacious in gestating and lactating bitches and their puppies at the proposed dose of 1 x 109 CFU/kg feed. This conclusion can be extrapolated to all dogs and other Canidae.

2.4.1. Conclusion on Section IV: Efficacy

Based on the efficacy study in dogs and the additional efficacy information provided by the applicant for the FSA/FSS submission, the ACAF concluded that the additive has the potential to be efficacious in dogs and all other Canidae at the proposed dose of 1 x 109 CFU/kg complete feed.

The FSA/FSS reviewed the ACAF’s advice on the updated efficacy data and agreed with the ACAF’s conclusions.

3. Analytical method evaluation

The FSA/FSS evaluated the EURL analytical method evaluation, noting it was carried out in 2015, when the UK was still part of the EU and would have participated of their approval. No concerns are raised at this stage for the validity of the methods for UK/GB use, and therefore the FSA/FSS accept the EURL analytical method evaluation report (EURL, 2015). The FSA/FSS determined the analytical method as appropriate for official controls for this feed additive.

4. Conclusions

In their 2016, 2019 and 2024 opinions, the FEEDAP Panel were satisfied with the identity and characterisation of both forms of the additive and the active agent. Stability and homogeneity data were provided in dog feed.

S. cerevisiae CNCM I-1079 is considered safe for the target species, the consumer and the environment. In 2024, the FEEDAP Panel concluded that both forms of the additive should be considered skin and respiratory sensitisers, and that any level of exposure is considered a risk. The non-coated form is not a skin or eye irritant, but the Panel could not conclude on the eye irritation potential of the coated form.

The FEEDAP Panel could not conclude on the potential efficacy of the additive in dogs and all other Canidae. Based on the efficacy trial in dogs and the additional efficacy information provided, the ACAF advised that the additive has the potential to be efficacious in gestating and lactating bitches and their puppies at the proposed dose of 1 x 109 CFU/kg feed. This conclusion can be extrapolated to all dogs and other Canidae.

5. Caveats and uncertainties

No caveats or uncertainties are noted.

6. FSA/FSS conclusions for GB risk analysis

The application has been assessed in line with the applicable guidance and is partially based on considerations of detailed proprietary information available to the Decision Panel, which were also submitted to the FSA and FSS. The EFSA opinions (EFSA FEEDAP Panel, 2016, 2019b, 2024) identify and characterise the hazards present which are also relevant to GB. The conclusions of the EFSA opinion alongside the efficacy assessment and conclusions reached by the ACAF have been reviewed in detail by the FSA and FSS and are considered appropriate and consistent, including the caveats and uncertainties identified in the opinion which are applicable to GB. Sufficient evidence has been demonstrated to conclude without further questions or risk assessment.

Abbreviations

Abbreviation Definition
ACAF Advisory Committee on Animal Feedingstuffs
CFU Colony forming units
CNCM Collection Nationale de Cultures de Microorganismes
CV Coefficient of Variation
DM Dry matter
EC European Commission
EU European Union
EFSA European Food Safety Authority
EURL European Union Reference Laboratories
FEEDAP EFSA Panel on Additives and Products or Substances used in Animal Feed
FSA Food Standards Agency
FSS Food Standards Scotland
GB Great Britain
IgA Immunoglobulin A
OECD Organisation for Economic Co-operation and Development
PSD Particle size distribution
QPS Qualified Presumption of Safety
UK United Kingdom
WGS Whole genome sequence

Acknowledgements

With thanks to the members of the ACAF during the course of the efficacy assessment, who were: Professor Nick Wheelhouse, Dr. Barry Bradford, Martin Briggs, Professor Emily Burton, Professor Katrina Campbell, Professor Nicholas Jonsson, Hannah Kane, Susan MacDonald, Christine McAlinden, Dr. Donald Morrison, Derek Renshaw, Dr. Michael Salter, Dr. Adam Smith, Professor Carla Viegas, Christel Wake and Dr. Helen Warren.