trends in monitoring residues of prohibited pharmacologically active substances in primary products...

Food Additives and Contaminants: Part BVol. 5, No. 3, September 2012, 212–220

Trends in monitoring residues of prohibited pharmacologically active substances in primary

products of animal origin in Lithuania and the European Union from 1999 to 2008

Loreta Sernien_ea*, Gintaras Daunorasb, Kristina Sudikienec, Gediminas Pridotkasc andMindaugas Malakauskasa

aDepartment of Food Safety and Quality, Lithuanian University of Health Sciences, Kaunas, Lithuania; bDepartment ofNon-Infectious Diseases, Lithuanian University of Health Sciences, Kaunas, Lithuania; cNational Food and Veterinary RiskAssessment Institute, Vilnius, Lithuania

(Received 20 June 2011; final version received 25 May 2012)

Group A pharmacologically active substances monitoring data in the Republic of Lithuania (LR) during theperiod 1999–2008 are presented. Peer review is based on data taken from residue monitoring plans of the years1999–2008 and the National Food and Veterinary Risk Assessment Institute (NFVRAI) reports on analysesperformed in various foods. The data were analysed with the SPSS statistical package, using descriptive statisticsand generalised linear modelling methods. Retrospective analysis of residue monitoring results showed that foodprocessed from animal products presented no risk to consumers as regards to substances of Group A1, A2, A3,A4 and A5. One substance of Group A6 (chloramphenicol) was detected in bovine milk in 2003 (9%), 2006 (2%)and 2008 (1.4%). The decreasing trend is confirmed by statistical data analyses, where year of monitoring(P� 0.0001), product (P� 0.1) and their interaction (P� 0.0001) proved the positive effect of the monitoringsystem.

Keywords: monitoring; prohibited substances of Group A; residues; primary products of animal origin

Introduction

Systematic analysis of food product composition was

initiated only in the final quarter of last century when

attention was not only paid to food nutritional

characteristics but also to food safety issues. Food

safety regulation and assurance is a complex process

involving all chain of food production – starting from

initial food production stages and finishing with

individual consumers. Major responsibility of food

safety assurance lays on food producers and govern-

ment. Consumers’ protection is of high priority in

European Union (EU) and common protection level is

very high. This is reflected in the precautionary

principle stated in Communication of European

Commission (European Commission 2000), which

endeavours a common approach as regards to detec-

tion, evaluation and management of risks that science

is not yet able to evaluate fully as well as making this

information available (Sirinskiene 2008). To reach the

required safety level, reliable data are required in order

to evaluate the risk properly and initiate the necessary

actions. Modern test methods are used to get data, and

they also have to be suitable for detection of a huge

variety of micro-contaminants (Navratilova 2008).

Animal husbandry establishments may use or are

using pharmacologically active substances – veterinarymedicinal products, feed additives, growth promotersetc. Veterinary medicinal products are used for treat-ment and prevention of diseases and they may beapplied individually or, quite often, to a group ofanimals with feed or drinking water (Boxall et al. 2004;Serratosa et al. 2006). Up to June 2009, use ofveterinary medicinal products for food-producing ani-mals was regulated by Council Regulation 2377/90/EC. In July 2009, the new Regulation (EC) No. 470/2009 of the European Parliament and of the Councillaying down Community procedures for the establish-ment of residue limits of pharmacologically activesubstances in foodstuffs of animal origin, repealingCouncil Regulation (EEC) No 2377/90, came intoforce. The prohibition on the use in stock farming ofcertain growth-promoting substances, hormones andbeta-agonists, is established by Council Directive96/22/EC, implemented in Lithuania as Regulationon prohibition on the use in stock farming of certainsubstances having a hormonal or thyrostatic actionand of beta-agonists (Regulation on usage, SFVS,Vilnius 2008).

Council Directive 96/23/EC establishes measures tocontrol (monitor) pharmacologically active substances,including contaminants, dyes, chemical elements etc. in

*Corresponding author. Email: [email protected]

ISSN 1939–3210 print/ISSN 1939–3229 online

� 2012 Taylor & Francis

http://dx.doi.org/10.1080/19393210.2012.698310

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live animals and animal products. This Directive isimplemented in Lithuanian law by the Rules on controlof certain substances and residues in live animals andanimal products (State Food and Veterinary Service2003; State Food and Veterinary Service 2008).Directive 96/23/EC divides all residues into GroupsA and B. Group A substances are prohibited sub-stances mentioned in Directive 96/22/EC and in annexIV of Regulation 2377/90/EC, as well as substancesstill not yet evaluated and therefore not allowed for usein food-producing animals. The Directive obliges EUmember states to monitor these substances in food-producing animals and animal by-products: meat,milk, eggs and honey. This means that samples fromlive animals on farm and carcasses at slaughterhousesshould be taken for testing. Directive 96/23/EC alsoobliges to perform a National residue-monitoringprogramme for latter substances by creating annualmonitoring plans. Monitoring of Group A substancesis of greater priority as these substances are importantfor public health. Therefore, comparatively moresamples are to be taken, and in case of positiveGroup A substance detection, more severe sanctionsmust apply. Presence of Group A substances in foodproducts and materials is of no doubt undesirable, isbased on scientific data and their monitoring is of greatimportance to ensure customer health. Monitoring ofundesirable substances in accordance with EU require-ments in Lithuania has been performed for 10 yearsalready, but until now the data have not beensummarised and analysed. Therefore, this study aimsto analyse monitoring data of Group A substances inLithuania during the period 1999–2008. It should servefor a possible opinion on retrospective contaminationof Lithuanian food with Group A pharmacologicallyactive substances as to ensure protection of publichealth.

Materials and methods

Plans for residue monitoring of 1999–2008 and reportson results of tests in various food products performedin the National Food and Veterinary Risk AssessmentInstitute (NFVRAI), formerly named NationalVeterinary Laboratory (NVL), were used for analysisof monitoring of Group A pharmacologically activesubstances in Lithuania. In 1998, the NVL started tocarry out contaminant monitoring plans. In accor-dance with the rules on monitoring of certain sub-stances and residues in animals and animal products,the plan for monitoring of residues in live animals andanimal products is drawn at the beginning of each year,and this plan serves as a basis for regional inspectorstaking samples. The samples are sent to and analysedin the NFVRAI Laboratory Department by validatedmethods of analysis (the department participates in the

FAPAS program). This department is assigned tocarry out the functions of national reference laboratory(NRL) by the Order of Director of State Food andVeterinary Service (SFVS), but samples for detectionof substances for which no method is available in placeare to be sent to relevant Community referencelaboratory or approved NRL of other EU memberstate. Monitoring plan is drawn following common EUcalculations on previous year’s production numbers,and number of samples accordingly is divided to everycounty individually. Control of implementation ofresidues-monitoring plan is done by SFVS, andNFVRAI has to coordinate and perform analysesforeseen in the Plan to prevent illegal use ofunauthorised substances and preparations to animals,to ensure application of uniform standards andmethods for substance and product testing and to docomparable tests of certain substances. SFVS presentsthe Plan for residues monitoring together with allthe data and results of the previous year analysesto European Commission (EC) not later than 31st ofMarch (State Food and Veterinary Service 2003).Up to 2001, the number of samples was calculatedaccording to production levels of approvedmanufacturing plants as they were able to pay for theanalyses. Since 2002 the residues monitoring financingsystem has been amended and calculation of number ofsamples was bound to county production levels.

SPSS statistical package was used to analyse 1999–2008 monitoring results presented to EC. Initialstatistical evaluation of data was done using descrip-tive statistics. Factors having influence on the numberof samples with exceeded MRL (noncompliant or‘‘positive’’ samples) were evaluated using the general-ised linear modelling univariate method. As factorsyear of analysis, type of food product analysed andinteraction of these factors were set, and as a variable,number of non-compliant samples of different phar-macologically active substances of Group A (appliedonly for oestradiol and chloramphenicol) was deter-mined. Significance of difference between groups (P)was determined using the least significant difference(LSD) method of comparisons. The difference wasconsidered statistically significant when P� 0.1.

Results and discussion

Residues monitoring in Lithuania started together withnegotiations on entering the European Union. For thefirst year, the food commodities most important forLithuanian producers were chosen for analysis –bovine, swine, poultry, egg and milk samples wereincluded into the first Plan according to whichLithuania was included in the list of countries fromwhich import of certain food products to EU wasallowed. This served as a base for food producers to

Food Additives and Contaminants: Part B 213

initiate trade and imports to EU. Later, taking intoaccount remarks of the EC and practical experience,the Plan was gradually amended by other samplegroups – honey, horses (since 2002 imports of livehorses to Italy started and samples of live animals –blood, urine – were taken for analysis mainly of GroupA substances, and when the slaughterhouse for horseswas approved by Lithuanian authorities in 2005,samples from slaughtered horses were included in thePlan), fish, farmed game etc.

Summary results of implementation of Plan formonitoring of residues of certain substances in animalsand animal products are presented in Table 1.

From the summarised results of Group A samples(Table 1, line ‘‘Total A’’), it can be seen that extent ofanalyses in samples of animal origin increased fromN¼ 747 (in 1999) to N¼ 1064 (in 2008), that is 42%during the 10-year period. Extent of analyses comes toa relatively steady state in 2003 and were approxi-mately N¼ 1000 during the past 6 years. In total, 8040samples of animal origin were taken for detection ofGroup A substances in the 10-year period. During thereviewed period, majority tests for Group A substanceswere done in bovine (N¼ 4270), porcine (N¼ 1449)and poultry (N¼ 833) meat and bovine milk (N¼ 698).Undoubtedly, these data are correlated with thenumber of food-producing animals and productionlevels in Lithuania. The least number of samples were

tested in game (N¼ 0), farmed game (N¼ 9), honey(N¼ 11) and sheep/goats (N¼ 18). The maximumnumber of samples for Group A substances in animalsand production groups was taken in 2008 (N¼ 1064);the minimum, in the year 2000 (N¼ 648). A commontendency in the implementation data in the plan formonitoring of residues of certain substances in animalsand animal products is that the number of samplestaken corresponds to numbers foreseen; therefore, thenumber of samples are proportionally set to thenumber of food-producing animals in the countrythat year and were at the same limits every year (e.g.number of poultry samples sent for testing wasapproximately N¼ 100). The EC does not requireany remarks on plan structure or implementation,except a request for inclusion of horses, honey and fishanalyses.

Factual number of tests performed in samplestaken from food-producing animals and productiongroups listed in Table 1 expressed by different GroupA substances and residue-positive samples during the1999–2008 monitoring period is presented in Table 2.

Table 2 shows that when summarising all separateanalyses, Group A substances were searched in 11,928samples during the research period in total. Themajority of tests were done for chloramphenicol(N¼ 1294), clenbuterol (N¼ 1071) and DES(N¼ 785). Analyses of these three substances

Table 1. Samples analysed in accordance with monitoring plans of 1999–2008 by animal and type of product.

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 Total in 10 years

Bovine AþB 1227 660 1468 925 1165 1054 1188 1165 1085 1168 11,105A 396 407 456 384 357 470 565 574 517 600 4726

Swine AþB 1014 372 338 591 807 828 766 771 775 762 175A 106 142 139 181 169 155 127 190 192 187 1588

Horses AþB – – – 33 18 20 22 28 23 31 175A – – – 33 18 20 22 26 21 23 163

Poultry AþB 332 117 102 103 196 211 204 189 181 182 1817A 182 51 50 48 101 107 72 90 81 101 883

Eggs AþB 75 34 200 173 581 542 220 199 202 202 2428A 14 5 50 29 152 91 46 45 45 47 524

Milk AþB 4161 1209 1528 1007 1517 1447 1499 1504 1496 1498 16,866A 15 38 45 102 139 94 98 72 65 75 743

Fish AþB 88 95 20 26 33 44 55 34 37 49 481A 34 5 6 4 11 10 6 6 8 7 97

Farmed game AþB – – – – – – – 1 4 20 9A – – – – – – – 1 0 8 9

Rabbits AþB – – – – 6 9 5 15 14 20 69A – – – – 2 2 1 5 6 8 24

Game AþB – 169 100 155 232 145 182 107 110 20 1220A – 0 0 0 0 0 0 0 0 0 0

Honey AþB 30 17 10 12 11 13 11 9 10 10 133A 0 0 0 0 1 2 1 2 2 3 10

Sheep/goats AþB – – – – 6 6 8 19 20 18 77A – – – – 3 3 1 6 0 5 18

Total AYB 6927 2673 4512 3025 4572 4319 4160 4041 3957 3980 43,340Total A 747 648 746 781 953 954 939 1017 937 1064 8785

Note: AþB¼ total number of samples for both groups; A¼ number of samples for A group substances.

214 L. Sernien _e et al.

Table

2.Number

ofsamplestested

(n)andnumber

ofpositivedetectionofGroupA

substances(þ

)duringthe10-yearmonitoringperiod.

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

Total

GroupA

substances

nþ

nþ

nþ

nþ

nþ

nþ

nþ

nþ

nþ

nþ

n

A1

Stilbenes

DES

89

0106

049

060

070

072

056

0107

095

081

0785

Hexestrol

89

072

0–

––

––

––

––

–107

095

081

0444

Dienestrol

89

066

0–

––

––

––

––

–107

095

081

0438

A2

Antithyroidal

substances

Thiouracil

65

02

010

059

064

096

083

01

077

065

0522

Methylthiouracil

65

02

010

065

0106

0–

––

–99

077

064

0488

Propylthiouracil

65

02

010

064

0106

0–

––

–99

077

064

0487

Phenylthiouracyl

––

––

––

––

––

––

––

––

77

064

0141

Mercaptobenzimidazol

––

––

––

––

––

––

––

––

77

064

0141

Tapazol

––

––

––

––

106

0–

––

–99

077

064

0346

A3

Steroids

Oestradiol

31

080

025

067

072

090

049

0123

0111

1112

0760

Testosterone

91

063

032

072

0109

0110

054

086

061

061

0739

Nortestosterone

20

038

0–

–28

036

050

035

073

0106

067

0453

Trenbolone

17

0–

–14

022

011

045

022

041

08

012

0192

Medroxyprogesterone

19

0–

––

––

–19

018

0–

––

––

––

–56

Chlorm

adinoacetate

––

––

––

––

––

––

––

––

––

10

1

A4

Resorcylic

acidlactones

Zeranol

31

0–

–31

026

057

079

050

096

099

079

0548

Taleranol

––

––

––

––

––

––

––

85

089

077

0251

A5

Beta-agonists

Clenbuterol

––

56

051

082

0109

099

093

0192

0212

0171

01065

Salbutamol

––

38

024

089

0–

––

––

––

––

––

–151

A6

Compounds

included

inAnnex

IVto

Reg.No2377/90

Chloramphenicol

49

069

097

0171

0277

25a

229

0205

0197

2b

197

0165

1b

1656

Furaltadone

––

––

––

43

0111

0–

––

–35

034

036

0259

Furazolidone

––

––

––

43

0112

0–

––

–35

034

035

0259

Nitrofurantoine

––

––

––

43

0111

066

029

035

034

010

0328

Total

720

0594

0353

0934

01476

25

954

0676

01617

21732

11454

110,510

Note:Differencesbetweensuperscripts

aandbare

statisticallysignificant(P�0.0001).


constitute 46% of total Group A testing by substances.Maximum amount of samples tested for Group Asubstances was in 2007 (N¼ 2587), and minimum in2001 (N¼ 353). The summarised number of samplesin Table 1 and the number of analyses in Table 2differ because the same sample was used for detectionof several substances. Available data show that themonitoring system brought positive effect: in 2003,25 samples from the total number tested for Group Asubstances were positive for chloramphenicol, andin 2006 this number decreased to 2, in 2008 to 1.The trend of decrease was also confirmed by statisticalanalyses: the effect of the year of monitoring,P� 0.0001; product, P� 0.1; and their interaction,P� 0.0001, are statistically significant. Table 2shows that in Lithuania the residue-monitoringresults are negative in most cases. For comparison,an analysis of tests for separate subgroups of Group Asubstances and data from other EU member statesare presented.

Analysis of Group A1 substances

Testing of three sub-group substances – diethylestrol(DES), hexestrol (HEX) and dienestrol (DEN) – wasforeseen in the Plan. Since 1998, these contaminantswere tested only in bovine, porcine and poultry meat,in 2000 fish samples and in 2001 horse samples wereadded to the group. During all reviewed periods, themaximum number of samples were tested from bovineanimals (N¼ 100, N¼ 281 and N¼ 104, respectively,for three substances), and the minimum from fish andhorses. In 2008, NFVRAI validated the confirmatorymethod for urine samples, that is, DCh/MS EI(method accredited and validated according toCouncil Decision 2002/657/EB), and CC� valueswere set as 0.65mg/L (DES), 0.62 mg/L (HEX) and0.75 mg/L (DEN). The outcome of the prohibition in1998 of use of anabolic steroids and other hormonalsubstances for food-producing animals in EU territoryis obvious: both in EU (in 1997–2007) and Lithuania(1999–2008), food materials were free of stilbeneresidues (European Commission 2008).


In 1999–2008, food materials were monitored for anti-thyroidal substance contamination: thiouracil,methylthiouracil, propylthiouracil and Tapazole resi-dues. Thiouracil residues have been monitored contin-uously till now. In 2002, thiouracil, methylthiouraciland propylthiouracil were foreseen to analyse inmuscle and plasma, and in 2003 Tapazole was addedto the group. These substances were most frequentlytested in bovine meat (N¼ 253, N¼ 179, N¼ 179 andN¼ 69, respectively) and fewer tests were done for

porcine and poultry meat, minimum number of sam-ples were for horses (N¼ 31, N¼ 17, N¼ 16 and N¼ 0,respectively). These four substances were included inthe Plan till 2007, and then during method validation,the analysis range was widened and now includesthiouracil (TU), Tapazole (TAP), 4-methyl-2-thiour-acil (MTU), 2-mercaptobenzimidazole (MBI),4-propyl-2-thiouracil (PTU) and 4-phenyl-2-thiouracil(PhTU). None of these contaminants were detected intested samples during the monitoring period. Since2000, non-compliant thiouracil group residues werenot detected in EU except in 2005 and 2007 whenFrance informed about eight bovine samples in whichthyreostatic residues were found. It was consideredthat these non-compliant results occurred because ofvery sensitive detection methods, and one of thepossible reasons for such occurrence is plants ofBrassicaceae family in bovine feedstuffs (EuropeanCommission 2008).


Since 1999, tests of Group A3 were done for oestradiol(in bovine and porcine meat and horses), testosterone(in bovine and porcine meat), nortestosterone, trenbo-lone and medroxyprogesterone (for bovine samplesonly). In 2003, trenbolone was started to be analysed inrabbit meat. In 2005, medroxyprogesterone was with-drawn from the Plan, and in 2007 the spectrum wasextended with �-nortestosterone, �-nortestosterone,�-boldenone and methyltestosterone monitoring. Thebiggest number of samples for these contaminants wastested in bovine animals (N¼ 182, N¼ 149, N¼ 55,respectively, for the first three substances). Only onenon-compliant sample was detected in this groupduring the reviewed period: in 2007, oestradiol con-centrations higher than the physiological bovine levelwas found in cow’s plasma (no statistically significanteffect of year, product or their interaction was found).Inspection results showed that blood sample was takenfrom the cow at the end of pregnancy just beforeparturition and in such a state the oestradiol concen-tration is naturally increased: testing of steroids inpregnant females is beside the purpose. Global studiesreveal that increased levels of hormones (e.g. nor-testosterone) may naturally occur in animals. The1997–2007 EU monitoring data show that countrieswith less developed animal husbandry assign up to0.1% of samples for Group A3 substance monitoring,and where animal husbandry is of greater importance(e.g. France, United Kingdom, Italy, Spain, Belgium,Netherlands and Germany) a greater number ofsamples is foreseen (0.2%–0.4%). The frequentlydetected residues are �-boldenone, epi-boldenone,nandrolone, stanozolone, progesterone and testoster-one – mainly in porcine and bovine samples.


Other commodities with non-compliance for steroids israre in EU countries (one positive fish sample wasreported by France in 2005). Some countries with highboldenone incidence (Italy, Netherlands) in theirannual reports additionally include �-boldenone,which supposedly may occur endogenically. An inter-esting fact is that during some years, corticosteroidsare found in the same EU countries. Percentage ofbovine samples containing hormone residues in EUvaried insubstantially in 1999–2007; the maximumnumber (0.55%) was in 2002, and minimum (0.09%)in 2000.


During 1999–2008, a total of 548 samples were testedfor zeranol. The maximum number of samples weretaken in 2004 (N¼ 79), and minimum in 2002 (N¼ 26).None of them was non-compliant for zeranol.

Other EU member states mainly use bovine sam-ples for Group A4 substances; number of porcinesamples is half of the bovine. Most commonly foundresidues are zeranol and taleranol. During the reviewedperiod of 1997–2007, samples non-compliant forzeranol were reported in Spain (porcine in 2000 and2003–2005); United Kingdom (bovine and sheep in2004, 2006, porcine in 2005); Germany, France andSpain (bovine in 2007); and Greece and Germany(poultry in 2007). Samples non-compliant for taleranolwere found in Germany and Italy in 2006 (EuropeanCommission 2008).


Testing of clenbuterol and salbutamol residues in foodmaterials and products was introduced in 2000 in

Lithuania; salbutamol residue testing was withdrawnin 2003 as other beta-agonists were chosen for analysis.The maximum number of samples were tested in 2007(N¼ 212), minimum in 2001 (N¼ 51). The biggestnumber of samples were analysed in 2002. Thesesubstances are tested in bovine and porcine samplesevery year in Lithuania. During the reviewed period,no residues of clenbuterol and salbutamol weredetected.

EU countries’ reports on Group A5 substancesmainly contain non-compliant clenbuterol residues.Most samples are reported from countries with highlydeveloped animal husbandry (Portugal, Spain, France,Netherlands and Italy) – especially bovine and porcineproduction. It should be noted that in the period of2000–2007, clenbuterol was present in Portugal and inquite high concentrations in bovine and porcinesamples. Reports state that the number of non-com-pliant samples with beta-agonists have been steadilydecreasing since 2004 (in 2005, only two countriesreported non-compliance instead of six), so the numberof samples for these substances is to be decreasedstarting from 2007 (4.0% lower than in 2006).


During the period reviewed, Lithuania tested residuesof chloramphenicol, furazolidone, furaltadone andnitrofurantoin. Chloramphenicol detection in foodmaterials started in 1998, followed by annual increasesin size (up to N¼ 200 since 2002). In total, N¼ 1294samples were tested for chloramphenicol during thereviewed period. Chloramphenicol residues were foundin cow’s milk in 2003 (69% of samples tested), and in2006 and 2008, 4% and 1.6% of samples tested,respectively (Table 3). These results confirm abuse of

Table 3. Results of chloramphenicol monitoring in food products during 1999–2008.

Samples

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

n þ n þ n þ n þ n þ n þ n þ n þ n þ n þ

Bovine 2 0 10 0 22 0 18 0 24 0 30 0 28 0 33 0 25 0 24 0Swine 2 0 12 0 0 0 1 0 13 0 23 0 28 0 28 0 46 0 27 0Poultry 12 0 4 0 1 0 22 0 18 0 13 0 11 0 11 0 16 0 4 0Fish 4 0 – – 1 0 1 0 4 0 4 0 2 0 3 0 4 0 2 0Ovine – – – – – – – – 2 0 – – – – 1 0 1 0 1 0Horses – – – – – – 13 0 – – – – – – – – 3 – 3 0Rabbits – – – – – – – – 2 0 – – 1 0 2 0 2 0 3 0Milk 15 0 38 0 66 0 102 0 139 25a 94 0 98 0 72 2b 65 0 69 1b

Eggs 14 0 5 0 7 0 14 0 75 0 63 0 31 0 31 0 21 0 17 0Honey – – – – – – – – – – 2 0 1 0 2 0 4 0 3 0Water – – – – – – – – – – – – 5 0 14 0 10 0 12 0

Total 49 0 69 0 97 0 171 0 277 25 229 0 205 0 197 2 197 0 165 1

Notes: n¼ number of samples tested; þ¼ positive for chloramphenicol. Differences between superscripts a and b are statisticallysignificant (P� 0.0001).


prohibited substance. Other compounds – thiamphe-nicol and florphenicol – are also used in EU countriesthat are chemically similar, but during the reviewedperiod mostly chloramphenicol was detected. Up to2004, chloramphenicol residues were reported bycountries with highly developed animal husbandry;most non-compliant samples were found in Belgium(1999), France (2000, 2001), Germany (2000–2002),United Kingdom (2001), Portugal (2001–2003),Austria (2002) and Italy (2003). From EU enlargementin 2004, chloramphenicol residues are almost annuallyreported in the Czech Republic, Estonia, Poland,Malta and Greece (European Commission 2008).According to RASFF (2007) data, the highest inci-dence of fish, meat and milk products contaminatedwith chloramphenicol and nitrofuranes was in 2002–2003.

Analysis of residues of nitrofurans (furaltadone[N¼ 260], furazolidone [N¼ 259] and nitrofurantoin[N¼ 2310]) has been included in the Lithuania Plansince 2002. These substances (formerly used as medic-inal products but at present prohibited) are frequentlydetected in meat but not in milk. Milk and milkproducts are the main products for export, so thiscommodity is of greatest importance in Lithuania(Zvirdauskiene et al. 2004). Although furazolidone,furaltadone and nitrofurantoin are tested in bovineand porcine samples, the amount and variety ofproducts for chloramphenicol testing increases withyears (see Table 3). Nevertheless, the majority ofsamples for Group A6 testing are taken from bovine,porcine and poultry samples both in Lithuania andother EU member states. EC reports state that mostcases of suspected samples are bovine and poultry.

Chloramphenicol is found in honey imported toEU from China and Argentina, seafood imported fromAsia (in 2001, tests in EU revealed chloramphenicolpresence in shrimps from Vietnam, which led todecreased Vietnamese shrimp imports to EU comparedwith 2000 and 2001–2003). In 2007 and 2008, UnitedKingdom reported nitrofurans in imported warm-water crustaceans (The Veterinary ResiduesCommittee 2008, 2009). Nitrofurans are also foundin porcine and poultry meat, shrimps, honey and eggpowder imported from third countries (FAO/WHOTechnical Workshop 2004).

Results of Group A6 substance monitoring showthat these substances present the greatest risk becauseof possible illegal use (abuse) in food-producinganimals in EU countries and Lithuania. Sampleanalysis shows that the most frequent possible abuseof these substances may occur in the primary stage offood production – on farms where animals are kept.This may occur when food-producing animals areillegally treated by preparations containing substancesof this group (parenteral, oral or local [ointment usedfor udder or hands of milking personnel]) application

and residues occur because of an insufficient with-

drawal period. These substances sometimes are inten-

tionally added to milk because of their antimicrobial

activity (Banovic et al. 2008). Residues of these

substances may be found in animal products imported

from third countries. Results show that particular

notice should be taken of Group A6 substance

monitoring in future residue monitoring plans, the

responsibility of animal food producers should be

intensified (Cannas da Silva et al. 2006), occurrence of

bigger farms should be encouraged, controls of imports

from other countries should be maintained at high

levels and stricter sanctions should be applied when

violations are found.Introduction of an additional non-statutory sur-

veillance scheme in Lithuania would be an option for

strengthening of residue control: additional samples

calculated according to the samples foreseen in the

Plan might be taken in possible critical points of local

and imported production chains (The Veterinary

Residues Committee 2008). Development of existing

analysis methods and establishing new ones during

cooperation with scientific institutions should be

considered more widely, and newly emerging more

precise methods should be used without any delay

(Zeleny et al. 2006; De Brabander et al. 2009;

Danaher and Prendergast 2010).In case of non-compliance as regards to prohibited

substances, particularly if serious abuse is suspected,

the NFVRAI reports the non-compliant results to the

SFVS, and the latter initiates checking of the farm

from which the non-compliant sample was taken. If

necessary, a special committee is established that is

responsible for imposing restrictions on animal move-

ment and preventing products from food-producing

animals from entering the food chain; establishing

the reason of prohibited substance occurrence in

the food chain; checking records on the farm and

at the responsible veterinarian; taking samples for

confirmation or repealing of previous results

and recommendations to send the samples to the

EU reference laboratory for analysis (State Food and

Veterinary Service 2003).Although residues of pharmacologically active

substances sometimes are found in various materials

of animal origin or in water, they are not always

confirmed in additionally taken blood or other sam-

ples. The possibility exists that the substances are

eliminated in body tissues and positive results cannot

be achieved or their residues are below detection limits

(Furusawa 2001).The scientific experience of developed countries

shows that monitoring and vigilance of undesirable

substances in food products of animal origin should

remain consistent and even continuously enhanced

(Jankovic et al. 2008).


Conclusions

Lithuanian SFVS successfully entered the monitoringsystem of undesirable substances in food materials andproducts that already existed in developed countriesand put their input into food safety insurance. Resultsof retrospective analyses of residue-monitoring testsshow that food products from animals during thereviewed period posed no risk to consumer safety asregards to A1, A2, A3, A4 and A5 groups ofsubstances. During the period analysed, only onesubstance of Group A6 (chloramphenicol) was foundin cow’s milk. Within the years of monitoring, decreaseof non-compliant samples with chloramphenicol resi-dues is statistically certified (P� 0.0001). The monitor-ing system of undesirable substances in food materialsand products in Lithuania was vindicated, and in futurethere is a need to strengthen the competence of allchains working in this field (regional SFVS centres,inspectors responsible for sample taking and NFVRAILaboratory Department) and precision of analyses.Also, it is important to find the possibility to implementcomplementary tests on certain substance residues.

During the reviewed period, violations are reportedmainly by the EU countries with highly developedanimal husbandry: France, United Kingdom, Italy,Spain, Belgium, Netherlands, Germany and Austria.Group A3 substances (corticosteroids) are continu-ously found at the same EU countries. Non-compliantcases of this group are difficult to analyse as some EUcountries attribute them to Group A (because of easiercontrol measures) and the others to Group B sub-stances (as other medicinal substances). During this10-year study period, cases of non-compliance ofGroup A contamination in food commodities in EUmember states were sporadic, mainly determined bytheir accidental access to food materials or disagree-ments about the exogenous origin of certain substancesand their presentation as non-compliance.

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