Sodium Bezoate EFSA 2779

EFSA Journal 2012;10(7):2779

Suggested citation: EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP); Scientific

opinion on the safety and efficacy of sodium benzoate as a silage additive for pigs, poultry, bovines, ovines, goats, rabbits

and horses. EFSA Journal 2012;10(7):2779. [15 pp.] doi:10.2903/j.efsa.2012.2779. Available online:

www.efsa.europa.eu/efsajournal

European Food Safety Authority, 2012

SCIENTIFIC OPINION

Scientific Opinion on the safety and efficacy of sodium benzoate as a silage

additive for pigs, poultry, bovines, ovines, goats, rabbits and horses1

EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP)2, 3

European Food Safety Authority (EFSA), Parma, Italy

ABSTRACT

Sodium benzoate is intended for use as a technological additive to improve the ensiling process at a proposed

dose of 2 400 mg/kg fresh matter, the eventual use of the silage being for pigs, poultry, bovines, ovines, goats,

rabbits and horses. The application of sodium benzoate in the preparation of silage at the proposed dose was safe

for the target animals. The proposed maximum dose of sodium benzoate is estimated to result in a comparable

consumer exposure as does its use as preservative in other feedingstuffs and to make a minimal contribution to

consumer exposure. The FEEDAP Panel concluded that sodium benzoate when used as a silage additive is safe

for the consumer. Sodium benzoate is not considered as a skin irritant but may be mildly irritant to the eyes. As

no data on sensitisation appear to be available, the FEEDAP Panel considered it prudent to treat sodium

benzoate as a potential sensitiser. In the absence of information on particle size and dusting potential, a risk from

inhalation cannot be excluded. The FEEDAP Panel concluded that there are no safety concerns for the

environment resulting from the use of sodium benzoate as a silage additive. Based on a series of laboratory

studies, sodium benzoate at the recommended dose was shown to have the potential to improve the production

of silage by reducing pH and increasing the preservation of dry matter. This was demonstrated in a range of

easy, moderately difficult and difficult to ensile forage materials. Sodium benzoate at concentrations between

250 and 2 500 mg/kg forage also has the potential to increase the aerobic stability of ensiled materials at a wide

range of dry matter content.

European Food Safety Authority, 2012

KEY WORDS

Technological additive, silage additive, sodium benzoate, safety, efficacy

1 On request from the European Commission, Question No EFSA-Q-2012-00416, adopted on 13 June 2012. 2 Panel members: Gabriele Aquilina, Georges Bories, Andrew Chesson, Pier Sandro Cocconcelli, Joop de Knecht, Nol

Albert Dierick, Mikolaj Antoni Gralak, Jrgen Gropp, Ingrid Halle, Christer Hogstrand, the late Reinhard Kroker,

Lubomir Leng, Secundino Lopez Puente, Anne-Katrine Lundebye Haldorsen, Alberto Mantovani, Giovanna Martelli,

Mikls Mzes, Derek Renshaw, Maria Saarela, Kristen Sejrsen and Johannes Westendorf. Correspondence:

[email protected] 3 Acknowledgement: The Panel wishes to thank the members of the Working Group on Silage for the preparatory work on

this scientific opinion.

Sodium benzoate for pigs, poultry, bovines, ovines, goats, rabbits and horses

EFSA Journal 2012;10(7):2779 2

SUMMARY

Following a request from the European Commission, the Panel on Additives and Products or

Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety for

the target animals, consumer, user and the environment and on the efficacy of the product sodium

benzoate, to be used as a technological additive intended to improve the ensiling process at a proposed

dose of 2 400 mg/kg fresh matter, the eventual use of the silage being for pigs, poultry, bovines,

ovines, goats, rabbits and horses.

The application of sodium benzoate in the preparation of silage up to the maximum proposed dose of

2 400 mg/kg forage was safe for the target animals.

The proposed maximum dose of sodium benzoate was estimated to result in a comparable consumer

exposure as does its use as preservative in other feedingstuffs and to make a minimal contribution to

consumer exposure. The FEEDAP Panel concluded that sodium benzoate when used as a silage

additive is safe for the consumer.

Sodium benzoate is not considered as a skin irritant but may be mildly irritant to the eyes. As no data

on sensitisation appear to be available, the FEEDAP Panel considered it prudent to treat sodium

benzoate as a potential sensitiser. In the absence of information on particle size and dusting potential,

a risk from inhalation cannot be excluded.

The FEEDAP Panel concluded that there are no safety concerns for the environment resulting from

the use of sodium benzoate as a silage additive.

Three studies with laboratory-scale silos are described, each lasting at least 90 days. In the first study,

sodium benzoate was added to ten forage materials covering a range of dry matter (DM) content (1928 %) with differing water-soluble carbohydrate content (WSC, 1.03.8 %). In the second study two batches of whole-crop maize, varying in DM (38.0 % and 45.1 %) and WSC contents (4.4 % and

2.9 %), were used and in the third study the forage treated was a corn cob mix (65.6 % DM and 1.5 %

WSC). In each case, replicate silos containing treated forage were compared with identical silos

containing the same untreated forage. The results showed that sodium benzoate at the recommended

dose has the potential to improve the production of silage by reducing pH and increasing the

preservation of DM. This was demonstrated in a range of easy, moderately difficult and difficult to

ensile forage materials. Sodium benzoate at concentrations between 250 and 2 500 mg/kg forage also

has the potential to increase the aerobic stability of ensiled materials at a wide range of DM contents.


EFSA Journal 2012;10(7):2779 3

TABLE OF CONTENTS

Abstract .................................................................................................................................................... 1 Summary .................................................................................................................................................. 2 Table of contents ...................................................................................................................................... 3 Background .............................................................................................................................................. 4 Terms of reference.................................................................................................................................... 4 Assessment ............................................................................................................................................... 6 1. Introduction ..................................................................................................................................... 6 2. Characterisation ............................................................................................................................... 6

2.1. Identity and properties of the active agent ................................................................................ 6 2.2. Stability ..................................................................................................................................... 7 2.3. Conditions of use ...................................................................................................................... 7 2.4. Evaluation of the analytical methods by the European Union Reference Laboratory (EURL) 7

3. Safety ............................................................................................................................................... 7 3.1. Safety for the target animals ..................................................................................................... 7 3.2. Safety for the consumer ............................................................................................................ 8 3.3. Safety for the user ..................................................................................................................... 9 3.4. Safety for the environment ........................................................................................................ 9

4. Efficacy ............................................................................................................................................ 9 Conclusions ............................................................................................................................................ 12 Documentation provided to EFSA ......................................................................................................... 13 References .............................................................................................................................................. 13 Appendix ................................................................................................................................................ 15


EFSA Journal 2012;10(7):2779 4

BACKGROUND

Regulation (EC) No 1831/20034 establishes the rules governing the Community authorisation of

additives for use in animal nutrition. In particular Article 10(2)/(7) of that Regulation specifies that for

existing products within the meaning of Article 10(1), an application shall be submitted in accordance

with Article 7, within a maximum of seven years after the entry into force of this Regulation.

The European Commission received a request from the company ADDCON EUROPE GmbH5 for re-

evaluation of the product sodium benzoate to be used as a feed additive for pigs, poultry, bovines,

ovines, goats, rabbits and horses (category: technological additive; functional group: silage additive)

under the conditions mentioned in Table 1.

According to Article 7(1) of Regulation (EC) No 1831/2003, the Commission forwarded the

application to the European Food Safety Authority (EFSA) as an application under Article 10(2)/(7)

(re-evaluation of an authorised feed additive). EFSA received directly from the applicant the technical

dossier in support of this application.6 According to Article 8 of that Regulation, EFSA, after verifying

the particulars and documents submitted by the applicant, shall undertake an assessment in order to

determine whether the feed additive complies with the conditions laid down in Article 5. The

particulars and documents in support of the application were considered valid by EFSA as of 2 April

2012.

This product was included in the European Union Register of Feed Additives following the provisions

of Article 10(1) of Regulation (EC) No 1831/2003.

TERMS OF REFERENCE

According to Article 8 of Regulation (EC) No 1831/2003, EFSA shall determine whether the feed

additive complies with the conditions laid down in Article 5. EFSA shall deliver an opinion on the

safety for the target animals, consumer, user and the environment and the efficacy of the product

sodium benzoate, when used under the conditions described in Table 1.

4 Regulation (EC) No 1831/2003 of the European Parliament and of the Council of 22 September 2003 on additives for use

in animal nutrition. OJ L 268, 18.10.2003, p. 29. 5 ADDCON Europe GmbH, Surestrasse 1, 06749, Bitterfeld-Wolfen, Germany. 6 EFSA Dossier reference: FAD-2010-0375.


EFSA Journal 2012;10(7):2779 5

Table 1: Description and conditions of use of the additive as proposed by the applicant

Additive Sodium benzoate

Registration number/EC

No/No -

Categoryof additive Technological

Functional group(s) of

additive Silage additive

Description

Composition, description Chemical

formula

Purity criteria

(if appropriate)

Method of analysis

Sodium benzoate C7H5O2Na >99.5%

European Pharmacopoeia,

Monograph 01/2008:0123

(titrimetric method)

Trade name not applicable

Name of the holder of

authorisation -

Conditions of use

Species or

category of animal

Maximum

Age

Minimum content Maximum content Withdrawal

period

mg or Units of activity or CFU/kg of complete

feedingstuffs (select what applicable)

pigs, poultry,

bovines, ovines,

goats, rabbits,

horses

n.a. - 2400 mg/kg fresh matter n.a.

Other provisions and additional requirements for the labelling

Specific conditions or restrictions for

use

n.a.

Specific conditions or restrictions for

handling

n.a.

Post-market monitoring

n.a.

Specific conditions for use in

complementary feedingstuffs

n.a.

Maximum Residue Limit (MRL)

Marker residue Species or category of

animal

Target tissue(s) or

food products

Maximum content in

tissues

n.a. n.a. n.a. n.a.


EFSA Journal 2012;10(7):2779 6

ASSESSMENT

1. Introduction

Sodium benzoate is intended to be added to forages to improve production of silage (technological

additive, functional group: silage additive) for pigs, poultry, bovines, ovines, goats, rabbits and horses.

Sodium benzoate is included in the European Union Register of Feed Additives pursuant to Regulation

(EC) No 1831/2003. A product (E 700) consisting of a mixture of sodium benzoate (140 g/kg),

propionic acid and sodium propionate is authorised as a feed additive for the preservation of cereals

with a moisture content of more than 15 %, at an inclusion rate of 322 g/kg cereal, for use in pigs and dairy cows

7 and cattle for fattening.

8 The FEEDAP Panel adopted an opinion on the re-evaluation of

the safety and efficacy of this additive as preservative of complete feedingstuffs at a maximum content

of 10 g/kg and for the use of treated feed (cereals and complete feedingstuffs) in poultry, bovines,

ovines, goats, rabbits and horses (EFSA, 2011a). The FEEDAP Panel has also adopted a scientific

opinion on the use of sodium benzoate as a feed additive for weaned piglets up to 35 kg body weight

at a dose of 4 g/kg complete feedingstuffs (EFSA, 2011b).

Sodium benzoate is approved as food additive (E 211) in the EU within the group of conditionally permitted preservatives (group of sorbates, benzoates and p-hydroxybenzoates). The additive can be used in food at the maximum levels indicated in the Council Directive No 95/2/EC and amendments.

9

Safety and toxicological aspects related to the food additive E 211 (pure-grade sodium benzoate) have

been assessed in opinions adopted and reports issued by different scientific committees and

organisations (World Health Organization, 2000; European CommissionEuropean Chemicals Bureau, 2000).

2. Characterisation

2.1. Identity and properties of the active agent

The additive under application is identical to the active substance, sodium benzoate, with Chemical

Abstracts Service (CAS) no 532-32-1 (European Inventory of Existing Chemical Substances

(EINECS) no 208-534-8), molecular formula C7H5NaO2, a molecular weight of 144.12 g/mol, and a

pKa of 4.19.

Sodium benzoate is produced in two steps: (1) oxidation of toluene to obtain benzoic acid, which is

purified by melt crystallisation and (2) addition of sodium hydroxide to the crude benzoic acid.10

The

resulting sodium benzoate solution is dried in a fluid bed granulation unit to obtain a white odourless

granular product with a density of 1.44 g/cm3 and water solubility of 560 g/L at 20 C.

The additive is by specification pure at 99.5 %. This was confirmed by the analysis of 45 batches of

the additive, which showed a mean content of 99.99 % of sodium benzoate on a dry matter (DM)

basis, with extremely small batch-to-batch variation (coefficient of variation < 0.01%).11

This meets

the specification of Directive 2008/84/EC laying down specific purity criteria on food additives other

7 Commission Regulation (EC) No 1876/2006 of 18 December 2006 concerning the provisional and permanent authorisation

of certain additives in feedingstuffs. OJ L 360 19.12.2006, p. 126. 8 Commission Regulation (EC) No 757/2007 of 29 June 2007 concerning the permanent authorisation of certain additives in

feedingstuffs. OJ L 172 30.06.2007, p. 43. 9 European Parliament and Council Directive No 95/2/EC of 20 February 1995 on food additives other than colours ad

sweeteners. OJ L 61 18.3.1995, p. 1. 10 Technical dossier/Section II/Annexes II_22 and 23. 11 Technical dossier/Section II/Table 2.1.3.1.


EFSA Journal 2012;10(7):2779 7

than colours and sweeteners.12

Potential impurities are controlled by specifications required by the

manufacturer.13

No data were provided to illustrate particle size distribution or dusting potential.

2.2. Stability

Sodium benzoate has a shelf-life of at least three years when the product is stored under recommended

conditions.14

Stability was tested in premixtures containing the additive in combination with other preservatives and

silage additives (such as sodium propionate, potassium sorbate, propionic acid, sodium nitrite,

hexamethylene tetramine). Sodium benzoate concentration (ranging between 10 % and 23 %) was

analysed in four different liquid premixtures (three batches for each premixture) at production and two

years later. The active substance was stable in premixtures (losses < 2 %) over a period of two years.15

Stability of sodium benzoate in silages was measured in a variety of samples (DM content ranging

from 20.6 % to 65.6 %) when added alone or in a premixture. In all studies (five) there were no

differences from the initial concentration after at least 90 days ensiling.16

Stability in water was not measured. However, as the stability of sodium benzoate was demonstrated

in silage after 90 days ensiling, this was not considered necessary.

2.3. Conditions of use

Sodium benzoate is intended to be used as silage additive in the nutrition of pigs, poultry, bovines,

ovines, goats, rabbits and horses. The additive has to be dissolved in water and then sprayed on forage

before ensiling at a maximum concentration of 2 400 mg/kg fresh matter.

2.4. Evaluation of the analytical methods by the European Union Reference Laboratory (EURL)

EFSA has verified the EURL report as it relates to the methods used for the control of the active agent

in animal feed. The executive summary of the EURL report can be found in the Appendix.

3. Safety

3.1. Safety for the target animals

No data on the tolerance of target species to sodium benzoate were provided. The FEEDAP Panel

therefore based its assessment on data for a feed additive consisting of a mixture of sodium benzoate

(140 g/kg additive), propionic acid and sodium propionate (referred to subsequently as organic

acid/salts mixture) when used as a feed additive for pigs, poultry, bovines, sheep, goats, rabbits, horses

(EFSA, 2011a). In that opinion, the FEEDAP Panel concluded, based on previous opinions by the

Scientific Committee for Animal Nutrition (EC, 2002a) and the FEEDAP Panel (EFSA, 2006) that this

additive is safe for pigs, dairy cows and cattle for fattening at a level of 22 000 mg/kg complete feed

(equivalent to 3 080 mg of sodium benzoate/kg complete feed or 3 500 mg/kg DM) (the margin of

safety being around five). In the same opinion, the Panel concluded that a level of 10 000 mg/kg

12 Commission Directive 2008/84/EC of 27 August 2008 laying down specific purity criteria on food additives other than

colours and sweeteners. OJ L 253 20.9.2008, p. 1. 13 Technical dossier/Section II/Annex II_1. 14 Technical dossier/Section II./Annex _II_1. 15 Technical dossier/Section II./Tables 2.4.1.2 and 2.4.1.3. 16 Technical dossier/Section II./Table 2.4.1.5.


EFSA Journal 2012;10(7):2779 8

complete feed (equivalent to 1 400 mg sodium benzoate/kg complete feed) was considered safe for

poultry, although the margin of safety could not be established.

The maximum proposed use in silage is 2 400 mg sodium benzoate/kg fresh matter. As silage usually

does not represent 100 % of the diet, the safe levels established for the organic acid/salts mixture can

be applied to the current use.

Pigs fed ensiled corn cob mix containing 2 400 mg sodium benzoate/kg silage as 60 % of the daily

ration would consume a diet containing between 2 880 and 2 060 mg sodium benzoate/kg DM, when

corn cob mix contains 50 % or 70 % DM, respectively.

For dairy cows, two exposure scenarios are described, one with a daily ration containing 40 % silage

(30 % DM), and another with a daily ration containing 50 % silage (50 % DM). The first scenario

would result in a concentration of 3 200 mg sodium benzoate/kg DM, the second in a concentration of

2 400 mg sodium benzoate/kg DM.

In the case of cattle for fattening, the use of higher levels of silage (up to 80 % of the total daily ration

with 30 % DM) would result in an intake of sodium benzoate of 6 450 mg/kg DM. This level is within

the margin of safety established by the FEEDAP Panel in the previous opinion (EFSA, 2006), in

which no adverse effects were observed in cattle for fattening receiving diets supplemented with the

equivalent dose of 7 700 mg sodium benzoate/kg complete feed.

According to the knowledge of the FEEDAP Panel, there is a low probability that silage will be used

in diets for poultry. Addition of 10 % silage (30 % DM) to a poultry diet would result in 800 mg

sodium benzoate/kg complete feed, which is below the level considered as safe for poultry (1400 mg

sodium benzoate/kg complete feed).

The safety of sodium benzoate has been established for dairy cows, cattle for fattening, poultry and

pigs, although with a low margin of safety. The FEEDAP Panel recognises that extrapolation of safety

to other species would normally require a margin of safety of at least ten. This would not be

possible/achievable for organic acids, which have narrow margins of safety.

Based on the data from dairy cows and cattle for fattening, safety for other ruminants can be

reasonably assumed. As silage use in horse (and rabbit) nutrition is much lower than in ruminants, the

FEEDAP Panel considers that use of sodium benzoate in silage for these species is safe at the

proposed use level. However, a margin of safety cannot be set for either species.

All the above considerations are made assuming that sodium benzoate is given only through silage,

and that complementary feed does not contain sodium benzoate used as a preservative.

3.2. Safety for the consumer

Sodium benzoate is authorised as food additive (E 211). An acceptable daily intake (ADI) of 5 mg/kg

body weight/day (equivalent to 300 mg/day for a 60 kg adult) has been established for benzoic acid

and its salts (JECFA, 1967, 1997, 2002; EC, 1994, 2002b).

The FEEDAP Panel considered the opinion of the Scientific Committee on Food (SCF) (EC, 2002c);

the SCF, noting that benzoic acid and related compounds gave positive results in some in vitro

genotoxicity studies in cultured mammalian cells, stated that all the in vivo genotoxicity tests were negative at somatic or germ cell level. The essentially negative results obtained in three

carcinogenicity studies (one in mice, two in rats) on sodium benzoate, notwithstanding some

limitations, give further reassurance. On this basis, it is very unlikely that benzoic acid would interfere

with chromosomes in vivo.


EFSA Journal 2012;10(7):2779 9

Since the SCF opinion of 2002, three relevant papers have been published. Two in vitro studies in

human lymphocytes with benzoic acid (Ylmaz et al., 2009) and its salts (Zengin et al., 2011) reported positive results in chromosomal aberration, sister chromatid exchange and micronucleus frequency.

The third study, an in vivo comet assay in mice, with benzoic acid and sodium benzoate reported no

induction of DNA damage in eight organs (Sasaki et al., 2002). The FEEDAP Panel considers that the

new studies would not require modification of the SCF position.

Calculation of consumer exposure based on the standard food basket given in Regulation (EC) No

429/2008 and on the guidance for establishing the safety of additives for the consumer of the FEEDAP

Panel (EFSA, 2012) showed that the additional exposure to benzoates when used as preservative for

feed will be 0.22 and 0.17 mg/person per day, respectively (EFSA, 2011a). The use of sodium

benzoate as a silage additive at a comparable concentration would be expected to lead to a similar

outcome.

The FEEDAP Panel concludes therefore, that sodium benzoate when used as silage additive is safe for

the consumer.

3.3. Safety for the user

The applicant submitted a review of the safety of benzoic acid and its salts that summarised the results

of studies in laboratory animals and observations in humans that form the basis of this assessment of

the user safety of sodium benzoate (WHO, 2000).

The results of an acute dermal irritation/corrosion study with rabbits conducted according to

Organization for Economic Cooperation and Development (OECD) Guideline 404 gave no indication

of skin-irritating effects. In a study performed according to OECD Guideline 405, sodium benzoate

was only mildly irritating to the eye (WHO, 2000).17

The WHO (2000) reported that no data on sensitising effects or inhalation toxicity of sodium benzoate

were identified in the available literature. Case reports and challenge studies indicate that skin

reactions caused by benzoic acid or sodium benzoate in a healthy general population are rare.

3.4. Safety for the environment

Benzoic acid and its derivatives are widely distributed in nature. After ingestion, they are converted to

hippuric acid (and ornithuric acid in galliformes and anseriformes) and excreted almost quantitatively

via the kidneys (EFSA, 2005). Such compounds have low potential for bioaccumulation, and the

available data on toxicity of benzoic acid and its salts to terrestrial/aquatic organisms indicates very

low toxicity (WHO, 2000).

The FEEDAP Panel concludes that there are no safety concerns for the environment resulting from the

use of sodium benzoate as a silage additive.

4. Efficacy

Results from three ensiling studies are reported. In these studies, the effects of different sodium

benzoate concentrations on the DM losses, fermentation pattern and aerobic stability of silages are

examined.

17 Technical dossier/Section III./Reference No 5.


EFSA Journal 2012;10(7):2779 10

Study 118

This multi-trial study included ten forage materials with a wide range of DM and water-soluble

carbohydrate (WSC) content (Table 2), which were classified as easy, moderately difficult or difficult

to ensile according to Regulation (EC) No 429/2008. Fresh and treated forages were filled into 2-L

glass jars. All treatments were applied in triplicate. Jars were stored for at least six months under

anaerobic conditions at a constant temperature of 25 C throughout the entire storage period.

The effect of sodium benzoate (2 000 mg/kg fresh forage matter), alone or in combination with other

silage additives, on pH, DM losses, fermentation pattern (ammonia-N and lactic, acetic and butyric

acids) and aerobic stability of silages was examined in comparison with a negative control. In this

opinion, only the data for the control and sodium benzoate groups (used as the only additive) are

considered. Treatments were compared within each forage crop. Data were analysed by analysis of

variance (ANOVA) when normal distribution was confirmed; if the distribution was not normal, an

ANOVA using rank numbers was applied.

Table 2: Classification of the ten forages according to their dry matter and water-soluble carbohydrate content

Trial Test material Cut Dry matter

(% fresh

matter)

Water soluble

carbohydrate content

(% fresh matter)

Classification

1 Dactylis glomerata 3 20.5 1.0 Difficult to

ensile 2 Trifolium pratense 2 18.5 1.1

3 Medicago sativa 2 27.9 1.3

4 Dactylis glomerata 3 22.3 1.4

5 Medicago sativa 1 24.1 1.6 Moderately

difficult to ensile 6 Lolium multiflorum 2 19.7 2.2

7 Lolium perenne 3 21.5 2.4

8 Phleum pratense 2 26.6 2.4

9 Phleum pratense 1 25.7 3.1 Easy to ensile

10 Trifolium pratense 1 24.4 3.8

Dry matter losses and ammonia-N were reduced by the addition of sodium benzoate in all forages

reaching significance in eight of the ten forage crops (Table 3). The additive increased lactic acid in

seven of the ten trials and decreased silage pH and butyric acid in eight of the ten forage crops. Nine

of ten treated silages were virtually free of butyric acid, indicative of reduced clostridial activity. The

effects of sodium benzoate were significant in forages easy, moderately difficult and difficult to ensile.

18 Technical dossier/Section IV./Annex_IV_1.


EFSA Journal 2012;10(7):2779 11

Table 3: Summary of the analysis of ensiled material recovered at the end of the experiments

Trial Sodium

benzoate

(mg/kg

fresh

forage)

DM loss

(%)

pH Lactic

acid

(% DM)

Acetic

acid

(% DM)

Butyric acid

(% DM)

Ethanol

(% DM)

Ammonia-N

(% of total N)

1 0 10.4 5.9 0.32 4.31 6.28 1.50 38.4

2 000 6.6* 4.7* 7.94* 5.53 0.0* 1.12* 16.9*

2 0 10.9 5.5 0.04 5.42 7.28 3.15 31.3

2 000 5.2* 4.2* 8.82* 5.18 0.07* 1.62* 7.7*

3 0 10.6 6.0 0.17 4.01 6.32 2.21 29.2

2 000 6.3* 4.7* 10.65* 5.53 0.0* 1.69* 13.3*

4 0 12.4 5.7 0.18 2.13 8.28 1.42 28.7

2 000 4.8* 4.4* 11.41* 2.49 0.05* 0.52* 12.3*

5 0 15.3 5.5 0.08 3.58 8.48 3.04 18.1

2 000 7.6* 4.6* 10.97* 5.11* 0.0* 3.00 8.4*

6 0 9.5 4.5 3.09 8.51 2.19 3.87 10.9

2 000 5.7 3.7* 14.81* 3.71 0.0 2.08 6.0

7 0 16.3 4.0 18.52 3.21 0.0 0.46 13.8

2 000 5.3* 4.1 15.47* 2.19* 0.0 0.49 12.7*

8 0 5.6 4.2 10.71 2.49 0.31 1.31 11.9

2 000 5.1 4.3* 7.71* 4.08* 0.0* 1.65 10.4*

9 0 11.5 5.2 1.37 0.65 5.00 3.62 15.5

2 000 6.8* 4.4* 9.74* 3.55* 0.0* 2.93* 9.1

10 0 7.6 4.1 16.44 4.25 0.07 2.82 11.8

2 000 6.6* 4.0 15.88 4.28 0.0* 1.97* 8.2*

DM, dry matter.

*Significantly different from control (P < 0.05).

The results showed that sodium benzoate has the potential to reduce clostridial activity (based on the

reduction in butyric acid) and proteolysis (based on reduction in ammonia-N) in silage fermentation,

and to reduce DM losses and pH and increase lactic acid concentration.

Study 219

Two batches of whole-crop maize, varying in DM (38.0 % and 45.1 %) and WSC (4.4 % and 2.9 %)

contents, were used to test the effects of the addition of sodium benzoate on the aerobic stability of the

silage. Forage was filled into 1.5-L glass jars and stored for 90 days under anaerobic conditions.

Sodium benzoate was applied at two rates (250 and 2 500 mg/kg). All treatments were applied in

triplicate. Jars were stored at 20 C throughout the fermentation period. The fermentation parameters

assessed were DM loss during fermentation, pH, lactic and acetic acids, ethanol and aerobic stability

upon exposure to air after silo opening (based on an increase in temperature of 2 C above ambient

upon exposure to air for 10 days).



EFSA Journal 2012;10(7):2779 12

Table 4: Summary of the analysis of ensiled material recovered at the end of experiments. Effects of two rates (250 and 2 500 mg/kg)

Sodium benzoate

(mg/kg fresh

forage)

DM loss

(%)

pH Lactic

acid

(% DM)

Acetic

acid

(% DM)

Ethanol

(% DM)

Aerobic

stability

(days)

Maize 38 % DM 0 5.3 3.6 5.4 1.2 2.4 7.5

250 5.4 3.8* 7.8* 1.1 2.2 10.0*

2500 4.0* 3.9* 7.4* 1.1 0.9* 10.0*

Maize 45 % DM 0 7.2 3.8 3.3 0.6 0.8 6.9

250 4.2* 3.8 3.7 0.7 0.8 10.0*

2500 4.0* 3.9* 3.0 0.9 0.5* 10.0*

DM, dry matter.

*Significantly different from control (P < 0.05).

Sodium benzoate significantly reduced DM loss and improved aerobic stability in both silages (Table

4).

Study 320

A corn cob mix (65.6 % DM and 1.5 % WSC) was used to test the effects of the addition of sodium

benzoate on the aerobic stability of the silage. Sodium benzoate was applied at two rates (250 and

2 500 mg/kg), and the selected fermentation parameters determined were DM loss, silage pH, lactic

and acetic acids, ethanol, aerobic stability upon exposure to air after silo opening (based on a

temperature increase of 2 C above ambient when the silage was opened) and DM loss upon exposure

to air for at least 22 days. Fresh and treated corn cob mix were filled into 1.5-L glass jars and stored

for either 60 or 105 days under anaerobic conditions at 25 C. All treatments were applied in triplicate.

Differences among treatments in fermentation pattern (pH, lactic and acetic acids and ethanol) were of

no practical relevance. Sodium benzoate at 2 500 mg/kg improved aerobic stability after 60 and 105

days ensiling (> 22 and > 27 days, respectively) in comparison with corresponding controls (16.3 and

11.9 days, respectively), whereas the lower application of 250 mg sodium benzoate/kg silage could

delay onset of aerobic deterioration only if silages had been stored for 105 days (15.7 vs. 11.9 days).

CONCLUSIONS

The application of sodium benzoate in the preparation of silage up to the maximum proposed dose of

2 400 mg/kg forage is safe for the target animals.

The proposed maximum dose of sodium benzoate is estimated to result in comparable consumer

exposure as does its use as preservative in other feedstuffs and to make a minimal contribution to

consumer exposure. The FEEDAP Panel concluded that sodium benzoate when used as a silage

additive is safe for the consumer.

Sodium benzoate is not considered as a skin irritant but may be mildly irritant to the eyes. As no data

on sensitisation appear to be available, the FEEDAP Panel considers it prudent to treat sodium

benzoate as a potential sensitiser. In the absence of information on particle size and dusting potential, a

risk from inhalation cannot be excluded.

The FEEDAP Panel concludes that there are no safety concerns for the environment resulting from the

use of sodium benzoate as a silage additive.



EFSA Journal 2012;10(7):2779 13

Sodium benzoate at the recommended dose has the potential to improve the production of silage by

reducing pH and increasing the preservation of DM. This was demonstrated in a range of easy,

moderately difficult and difficult to ensile forage materials. Sodium benzoate at concentrations

between 250 and 2 500 mg/kg also has the potential to increase the aerobic stability of ensiled

materials at a wide range of DM content.

DOCUMENTATION PROVIDED TO EFSA

1. Sodium benzoate. November 2010. Submitted by ADDCON EUROPE GmbH.

2. Evaluation report of the European Union Reference Laboratory for Feed Additives on the Methods of Analysis for Sodium benzoate.

3. Comments from Member States received through the ScienceNet.

REFERENCES

EC (European Commission), 1994, online. Reports of the Scientific Committee for food (Thirty-fifth

series). Available from http://ec.europa.eu/food/fs/sc/scf/reports/scf_reports_35.pdf

EC (European Commission), 2002a, online. Opinion of the Scientific Committee for Animal Nutrition

on the use of KofaGrain pH5 (a mixture of sodium benzoate, propionic acid and sodium

propionate) in feedingstuffs for pigs, cattle for fattening and dairy cows. Available from

http://ec.europa.eu/food/fs/sc/scan/out84_en.pdf

EC (European Commission), 2002b, online. Scientific Committee on Cosmetic Products and Non-

Food Products Intended for Consumers. Opinion of the scientific committee on cosmetic products

and non-food products intended for consumers concerning benzoic acid and sodium benzoate.

Available from http://ec.europa.eu/food/fs/sc/sccp/out166_en.pdf

EC (European Commission), 2002c, online. Opinion of the Scientific Committee on Food on Benzoic

acid and its salts. Available from http://ec.europa.eu/food/fs/sc/scf/out137_en.pdf

EC (European Commission), 2005b, online. Scientific Committee on Consumer Products, 2005.

Opinion on Benzoic Acid and Sodium Benzoate. Available from

http://ec.europa.eu/health/ph_risk/committees/04_sccp/docs/sccp_o_015.pdf

EFSA (European Food Safety Authority), 2005. Opinion of the Scientific Panel on additives and

products or substances used in animal feed (FEEDAP) on the Safety and Efficacy of the product

VevoVitall as a feed additive for weaned piglets in accordance with Regulation (EC) No

1831/2003. The EFSA Journal, 290, 113.

EFSA (European Food Safety Authority), 2006. EFSA Panel on Additives and Products or Substances

used in Animal Feed (FEEDAP); Opinion of the Scientific Panel on Additives and Products or

Substances used in Animal Feed on the safety and efficacy of KofaGrain -pH 5- (a mixture of

sodium benzoate, propionic acid and sodium propionate) as a feed additive for cattle for fattening.

The EFSA Journal, 408, 112.

EFSA (European Food Safety Authority), 2011a. EFSA Panel on Additives and Products or

Substances used in Animal Feed (FEEDAP); Scientific Opinion on safety and efficacy of sodium

benzoate, propionic acid and sodium propionate for pigs, poultry, bovines, ovines, goats, rabbits,

horses. EFSA Journal, 9(9):2357.

EFSA (European Food Safety Authority), 2011b. EFSA Panel on Additives and Products or

Substances used in Animal Feed (FEEDAP); Scientific Opinion on Safety and efficacy of Protural

(sodium benzoate) as feed additive for weaned piglets. EFSA Journal, 9(2):2005.


EFSA Journal 2012;10(7):2779 14

EFSA (European Food Safety Authority), 2012. EFSA Panel on Additives and Products or Substances

used in Animal Feed (FEEDAP); Guidance for establishing the safety of additives for the

consumer. EFSA Journal, 10(1):2537.

European Commission-European Chemicals Bureau, online, 2000. IUCLID Dataset: IUCLID on

sodium benzoate (CAS# 532-32-1). Available from http://esis.jrc.ec.europa.eu/doc/existing-

chemicals/IUCLID/data_sheets/532321.pdf

JECFA, 1967. 10. Report: Toxicological evaluation of certain food additives. 10th report of the joint

FAO/WHO Expert Committee on the Food Additives. WHO Technical Report Series No 373.

Geneva: World Health Organization.

JECFA, 1997. Evaluation of certain food additives and contaminants. 46th report of the Joint

FAO/WHO Expert Committee on Food Additives 1996. WHO Technical Report Series NO 868.

Geneva: World Health Organization.

JECFA, 2002. Evaluation of certain food additives and contaminants. 57th report of the Joint

FAO/WHO Expert Committee on Food Additives. WHO Technical Report Series No 909. Geneva:

World Health Organization.

Sasaki YF, Kawaguchi S, Kamayaa A, Ohshita M, Kabasawa K, Iwamaa K, Taniguchi K, Tsuda S,

2002. The comet assay with 8 mouse organs: results with 39 currently used food additives.

Mutation Research 519, 103119.

World Health Organization, online, 2000. International Programme on Chemical Safety (IPCS),

Concise International Chemical Assessment Document (CICAD) No. 26. Benzoic acid and sodium

benzoate. Available from http://www.inchem.org/documents/cicads/cicads/cicad26.htm or

http://www.who.int/ipcs/publications/cicad/cicad26_rev_1.pdf

Ylmaz S, Unal F and Yuzbasioglu D, 2009. The in vitro genotoxicity of benzoic acid in human peripheral blood lymphocytes. Cytotechnology 60, 5561.

Zengin N, , Unal F, Ylmaz S and Aksoy H, 2011. The evaluation of the genotoxicity of two food preservatives: Sodium benzoateand potassium benzoate. Food and Chemical Toxicology 49, 763769.


EFSA Journal 2012;10(7):2779 15

APPENDIX

Executive Summary of the Evaluation Report of the European Union Reference Laboratory for

Feed Additives on the Methods of sodium benzoate for pigs, poultry, bovines, ovines, goats,

rabbits and horses21

In the current application authorisation is sought under article 10(2) for sodium benzoate under the

category / functional group 1(k) of 'technological additives'/'silage additives', according to the

classification system of Annex I of Regulation (EC) No 1831/2003. Specifically, authorisation is

sought for the use of the feed additive for bovines, sheep, pigs, poultry, rabbits, horses, goats.

According to the Applicant, the feed additive is a white, odourless, solid substance. The feed additive

consists of sodium benzoate, with a minimum purity of 99.5 %. The feed additive is intended to be

used in silage, with a proposed maximum level of 2.4 g/kg silage.

For the determination of sodium benzoate in the feed additive the Applicant proposed the European

Pharmacopoeia Monograph (01/2008:0123), where: - identification is based on the sodium and on the

benzoate reactions, while - quantification is based on the titration of sodium benzoate with 0.1 M

perchloric acid, using naphtholbenzein as an indicator.

Even though no performance characteristics are provided, the EURL recommends for official control

the above mentioned European Pharmacopoeia Monograph to determine sodium benzoate in the feed

additive.

For the quantification of sodium benzoate in silage the Applicant submitted a single-laboratory

validated and further verified method, based on high performance liquid chromatography with UV

detection (HPLC-UV). The following performance characteristics were reported for sodium benzoate

concentrations ranging from 215 to 2620 mg/kg: - a relative standard deviation for repeatability (RSDr) ranging from 0.6 % to 12 %; - a recovery rate (Rrec) ranging from 103 to 109 %; and - a limit

of quantification (LOQ) of 125 mg/kg silage.

Based on the performance characteristics presented, the EURL considers the single laboratory

validated and further verified HPLC-UV method suitable for the determination of sodium benzoate in

silage. However, the unambiguous determination of the content of sodium benzoate added to silage

cannot be performed satisfactorily due to intrinsic properties of silage matrice. Therefore, the EURL

cannot recommend this method for official control to determine added sodium benzoate in silage.

Further testing or validation of the methods to be performed through the consortium of National

Reference Laboratories as specified by Article 10 (Commission Regulation (EC) No 378/2005) is not

considered necessary.

21 The full report is available on the EURL website:

http://irmm.jrc.ec.europa.eu/EURLs/EURL_feed_additives/authorisation/evaluation_reports/Pages/index.aspx

Documents

Sodium Bezoate EFSA 2779