Efficacy of calcium formate as a technological feed additive (preservative) for all animal species

Abstract

In 2015, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) issued an opinion on the safety and efficacy of ammonium formate, calcium formate and sodium formate when used as a technological additive (preservative) for all animal species. Calcium formate was considered safe for all animal species at a maximum concentration of 10,000 mg formic acid equivalents/kg complete feed (with the exception of pigs, for which a maximum concentration of 12,000 mg formic acid equivalents/kg complete feed was considered safe). Calcium formate was also considered safe for the consumer and the environment. The Panel also concluded that calcium formate is non‐irritant to the skin, but mildly irritant to the eyes, and is a respiratory irritant with a potential for sensitisation. The Panel also concluded that ‘Calcium formate or solid sodium formate had no discernible effects on microbial numbers in the feed materials examined. The preservative effect of the three formate salts in water for drinking was not demonstrated’. In the current opinion, additional data to demonstrate the efficacy of calcium formate as a preservative in feed for all animal species were assessed. The Panel concluded that calcium formate has the potential to be efficacious as a preservative in feedingstuffs for all animal species at the proposed use level. In the absence of data, the Panel cannot conclude on the efficacy of the use of the additive in water for drinking.

1. Introduction

1.1. Background and Terms of Reference as provided by the requestor

Regulation (EC) No 1831/2003 establishes rules governing the Community authorisation of additives for animal nutrition and, in particular, Article 9 defines the terms of the authorisation by the Commission.

The applicant, FEFANA ASBL, is seeking a Community authorisation for calcium formate (E 238) as a feed additive to be used as a preservative for all animal species (Table 1).

Table 1.

Description of the substances

Category of additive	Technological additives
Functional group of additive	Preservative
Description	Calcium formate (E238)
Target animal category	All animal species
Applicant	FEFANA ASBL
Type of request	New opinion

On 11 March 2015, the Panel on Additives and Products or Substances used in Animal Feed of the European Food Safety Authority (“Authority”), in its opinion on the safety and efficacy of the product, could not conclude on the efficacy of sodium formate (E237), calcium formate (E238) and ammonium formate (E295) as preservative for compound feed or feed materials. After the discussion with the Member States on the Standing Committee, it was suggested to check for the possibility to demonstrate the efficacy.

The Commission (EC) gave the possibility to the applicant to submit complementary information in order to complete the assessment and to allow a revision of the Authority's opinion. The new data have been received on 29 August 2019.

In view of the above, the Commission asks the Authority to deliver a new opinion on calcium formate (E 238) as a feed additive for all animal species based on the additional data submitted by the applicant.

1.2. Additional information

Calcium formate (E 238) is currently listed in the EU Register of Feed Additives as a technological additive (functional group: preservative) for use in feed for all animal species. The re‐evaluation of calcium formate as a technological additive (functional group: preservative) for use in feed for all animal species is the subject of the current application.

The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) delivered in 2015 and opinion on the safety and efficacy of ammonium formate, calcium formate and sodium formate when used as a technological additive (preservative) for all animal species (EFSA FEEDAP Panel, 2015). In this opinion, the FEEDAP Panel concluded that ‘Calcium formate or solid sodium formate had no discernible effects on microbial numbers in the feed materials examined. The preservative effect of the three formate salts in water for drinking was not demonstrated’. The applicant has now submitted additional data to demonstrate the efficacy of calcium formate as a preservative in feed for all animal species.

2. Data and methodologies

2.1. Data

The present assessment is based on the data submitted by the applicant in the form of additional information1 following a previous application on the same product.2

2.2. Methodologies

The approach followed by the FEEDAP Panel to assess the efficacy of calcium formate is in line with the principles laid down in Regulation (EC) No 429/20083 and the relevant guidance documents: Guidance on the assessment of the efficacy of feed additives (EFSA FEEDAP Panel, 2018).

3. Assessment

The additive under assessment is calcium formate. The additive is intended to be used as a technological additive, functional group preservative in feedingstuffs and water for drinking for all animal species. The proposed maximum contents in feed are of 12,000 mg/kg complete feed for pigs and a 10,000 mg/kg feed for all the other species, all expressed as formic acid/kg complete feed. The corresponding maximum content in water for drinking is 4,000 mg/L for all animal species, with the exception of ruminants, for which a maximum content is not proposed. The additive was fully characterised in the previous opinion the safety and efficacy of ammonium formate, calcium formate and sodium formate when used as a technological additive for all animal species (EFSA FEEDAP Panel, 2015). Calcium formate was considered safe for all animal species at a maximum concentration of 10,000 mg formic acid equivalents/kg complete feed (with the exception of pigs, for which a maximum concentration of 12,000 mg formic acid equivalents/kg complete feed was considered safe). Calcium formate was also considered safe for the consumer and the environment. The Panel also concluded that calcium formate is non‐irritant to the skin, but mildly irritant to the eyes, and is a respiratory irritant with a potential for sensitisation.

Regarding the use of the additive as preservative in feedingstuffs, based on the available data the Panel concluded that ‘calcium formate had no discernible effects on microbial numbers in the feed materials examined’. In addition, no data were provided to support the efficacy as a preservative in water for drinking.

The applicant has now provided additional data to support the efficacy of calcium formate as a preservative in feedingstuffs for all animal species. No new data on the efficacy of calcium formate in water for drinking were provided.

3.1. Efficacy

The endpoints to demonstrate the efficacy of an additive in the functional group preservative is ‘inhibition of microbial growth, particularly that of biotic and spoilage organisms. The period for which a preserving effect is claimed shall be demonstrated’.3

To support the efficacy of calcium formate as preservative in feedingstuffs for all animal species, three in vitro studies were provided.

3.1.1. Study 1 – Totally mixed ration

In the first study, a totally mixed ration (TMR) was prepared with 52% grass silage, 37% corn silage, 7.6% crimped wheat, 2.9% protein feed, 0.3% minerals and 0.25% salt. The dry matter (DM) content was approx. 43%. Three representative samples of the TMR were collected at study start to determine DM content, pH, and yeasts, moulds and total aerobic counts. The TMR was either left untreated (control, six replicates (350 g fresh matter (FM) each, in test tubes of 1,300 mL)) or treated with 3.0 g calcium formate/kg fresh TMR (six replicates). These samples were exposed to an aerobic environment (20 ± 1°C ambient temperature and 60–70% relative humidity) while their core temperatures were monitored. The lower end of the tubes was covered with an autoclaved, woven fabric to allow air to pass through. Sample temperatures were recorded every second hour for a period of 5.3 days. Three replicates each were removed and analysed for pH, yeasts, moulds and total aerobic counts when the control samples went 5°C above the ambient temperature (T1). The remaining samples were analysed when the treated TMR reached the same temperature difference (T2).

The data were analysed statistically using a one‐way analysis of variance (ANOV)A. Significance was set a p < 0.05.

At T1, treated samples, compared to the control, showed a significantly lower pH values (4.34 vs 4.45), significantly lower counts for yeasts (6.35 vs 7.50 log CFU/g) and total aerobic (6.63 vs 7.59 log CFU/g). At T2, the differences in pH became more marked (4.59 vs 6.12) and remained significant for yeast count (7.97 vs 8.43 log CFU/g) and total aerobic (7.91 vs 8.66 log CFU/g). T2 was reached 1.8 days after the T1.

3.1.2. Study 2 – Beet pulp

In the second study, that followed the same protocol described for Study 1, beet pulp (DM 27.5%) samples (660 g FM each, in test tubes of 1,300 mL) were analysed for aerobic stability and DM content, pH, and yeast, moulds and total aerobic counts.

At T1, treated samples, compared to the control, showed a significantly lower pH values (3.66 vs 3.95), significantly lower counts for yeasts (5.06 vs 7.26 log CFU/g) and total aerobic bacteria (6.73 vs 8.53 log CFU/g). At T2, that was reached 1.9 days after the T1, only yeasts counts were different between the treated and the control samples (6.79 vs 7.88 log CFU/g, respectively).

3.1.3. Study 3 – Distiller's grains

Distiller's grains as a high moisture feed ingredient (8.2% DM), was taken for the third study. Distiller's grains were mixed with Ca‐formate at 0 or 3.0 g/kg fresh matter. Twelve test tube (500 ml volume, filled with 250 ml distiller's grains) for each treatment were stored at ambient temperature (20 ± 2°C). Once a day, samples were mixed manually for approximately 10 minutes to homogenize and to increase the aeration intensity. Sample temperatures were recorded every two hours. Three tubes per treatment were removed and analysed for pH, yeast, mould and total aerobic count after 17, 24, 33 and 40 days (T1, T2, T3 and T4).

No differences were observed along the study in aerobic stability and in pH between the control and the Ca‐formate treated distiller's grains. At all the sampling times the treated samples, compared to the control, showed a significantly lower counts for yeasts (T1: <1.70 vs 7.11 log CFU/g, T2: 2.87 vs 6.61 log CFU/g, T3: 4.45 vs 7.19 log CFU/g, T4: 2.39 vs 6.97 log CFU/g). Total aerobic bacteria count was affected only at T4 (9.38 vs 9.04 log CFU/g in treated and control, respectively), as well as moulds count (4.16 vs < 1.70 log CFU/g in treated and control, respectively).

4. Conclusions

The results of three in vitro studies with compound feedingstuffs and feed materials showed that calcium formate has the potential to be efficacious as a preservative in feedingstuffs for all animal species at the proposed use level. In the absence of information on the efficacy of calcium formate in water for drinking, the Panel cannot conclude on the efficacy of the use of the additive in water.

5. Documentation as provided to EFSA/Chronology

Date	Event
11/11/2019	Dossier received by EFSA ‐ Calcium formate. Submitted by FEFANA asbl
11/11/2019	Mandate received by EFSA
19/03/2020	Opinion adopted by the FEEDAP Panel. End of the Scientific assessment

Abbreviations

ANOVA

analysis of variance

CFU

colony forming unit

DM

dry matter

FEEDAP

EFSA Panel on Additives and Products or Substances used in Animal Feed

FM

fresh matter

TMR

totally mixed ration

Suggested citation: EFSA FEEDAP Panel (EFSA Panel on Additives and Products or Substances used in Animal Feed) , Bampidis V, Azimonti G, Bastos ML, Christensen H, Dusemund B, Kos Durjava M, Kouba M, López‐Alonso M, López Puente S, Marcon F, Mayo B, Pechová A, Petkova M, Ramos F, Sanz Y, Villa RE, Woutersen R, Aquilina G, Bories G, Gropp J, Nebbia C and Innocenti ML, 2020. Scientific Opinion on the efficacy of calcium formate as a technological feed additive (preservative) for all animal species. EFSA Journal 2020;18(4):6077, 6 pp. 10.2903/j.efsa.2020.6077