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National Programme for Monitoring and Surveillance of Chemical Residues in Raw Milk

- Plan for 1 July 2008 to 30 June 2009

June 2008

Version 01

Important Disclaimer

Every effort has been made to ensure the information in this report is accurate.

NZFSA does not accept any responsibility or liability whatsoever for any error of fact, omission, interpretation or opinion that may be present, however it may have occurred.

Further copies

Requests for further copies should be directed to:
New Zealand Food Safety Authority
P O Box 2835
WELLINGTON
Telephone : (04) 894-2500
Fax : (04) 894-2501

Website
A copy of this document can be found at www.nzfsa.govt.nz

Table of Contents

1 Preamble 3

2 Sampling Plan 4

2.1 Statistical Confidence 4

2.2 Sample Numbers 5

2.3 Random Monitoring & Seasonal Distribution 5

2.4 Directed (Targeted) Surveillance 7

2.5 Determination of compounds to screen 7

3 Substances & Analytes for 2008/2009 8

3.1 Group A: Substances having anabolic effect and unauthorised use 8

3.2 Group B: Veterinary drugs and contaminants 10

3.3 Substances and residues to be monitored in 2008/09 14

1 Preamble

Dairy monitoring and surveillance programmes for selected substances have been in operation throughout New Zealand for many years, and a programme was introduced in the 1996/97 dairy season. Since this time the programme has become incorporated under the Dairy Industry (National Residue Monitoring Programme) 2002, and administered by the New Zealand Food Safety Authority (NZFSA).

New Zealand’s monitoring and surveillance programme is designed to audit the effectiveness of the regulatory controls in place for ensuring chemical residues in dairy products do not pose a threat to human health, that good agricultural practices are being followed and that all relevant importing country requirements will be met. In addition surveys aimed at identifying new risk factors or better defining potential issues, are undertaken as necessary.

The monitoring programme is regarded as verification, not a primary control measure. It identifies where controls may not be working and enables an appropriate investigation to be undertaken to determine the cause and required corrective actions.

Regulatory reactions to identified ‘control failures’ are aimed at motivating not just the individual farmer or factory directly concerned but the whole sector responsible for that control to make the necessary adjustments.

The types of chemicals analysed for, the number of samples to be analysed, and the sampling pattern have been determined following consideration of factors relevant to New Zealand farming practices. Due consideration has been taken of historical monitoring results which have thus far indicated the current controls have been effective in ensuring chemical residues in dairy products conform to applicable limits.

The level of monitoring to some extent also reflects the severity of sanctions currently applied to transgressors. In New Zealand, dairy risk management programme (RMP) operators apply severe penalties when milk supplies fail the inhibitory substances test, and NZFSA applies strict rules concerning traceback, corrective action and, if any dairy material or product is found to be non-compliant, disposition under NZFSA control.

Factors taken into consideration in the design of the programme include:

• residue and toxicological potential of the substance,

• potential for misuse or abuse,

• extent and pattern of use within New Zealand,

• previous residue non-compliance, and

• persistence in the environment.

Substances which are of interest to importing countries may be included where appropriate, irrespective of whether there is any evidence or likelihood of use or abuse in New Zealand.

Action limits are established for all residues of primary interest in the programme. Where Maximum Residue Limits (MRL’s) have been set, the action limit is the lower of the New Zealand, Codex, and Importing Country MRL’s. Where a compound is banned or not for use on milking animals the action limit is set at the minimum reporting limit.

The substantial analysis undertaken per sample enables New Zealand to provide assurances that Good Agricultural Practices are being followed and MRL’s met under the New Zealand regulatory programme.

2 Sampling Plan

Consistent with Codex Alimentarius guidelines, New Zealand utilises a scientifically and statistically justified, risk-based approach to monitoring chemical residues in raw milk.

The programme consists of three parts, random monitoring, directed surveillance and surveys. The monitoring programme is a non-biased sampling programme and is designed to provide profile information on the occurrence of residues in raw milk and colostrum on a national basis.

All random monitoring for raw milk under the New Zealand programme is sampled from the farm bulk milk tank prior to consolidation or dilution through the collection and manufacturing process. This ensures that Good Agricultural Practice is monitored as well as conformance at the farm to residue MRLs and applicable limits for other chemical contaminants.

2.1 Statistical confidence

Consistent with Codex guidelines, New Zealand uses statistically based sample sizes. In the monitoring component of the NCCP, the numbers of samples taken is aligned with that required to provide a 95% confidence of being able to detect an incidence of non-compliance in the population of 1% or greater. This means that a minimum of 300 official random monitoring samples must be taken each year for analysis of the core compounds to be monitored. This minimum covers all bovine farms producing milk eligible for export (over 99% of New Zealand dairy farms). Additional samples are taken for other species (caprine and ovine) and bovine domestic milk.

2.2 Sample numbers

A minimum of 322 random raw milk and 60 directed colostrum samples are to be taken by the NCCP in 2008/09.

Monitoring under the New Zealand programme is equivalent to 1 sample per 39,529 tonnes of the annual production of milk, or 1 sample per 30 herds. In New Zealand the average milk supply is above 5,600 litres per consignment.

Table 1: Farm production

	New Zealand
Litres/farm/season	1,237,228
Milking animals/farm	337

Currently New Zealand also subjects every sample collected to every test scheduled in the particular random monitoring round. By subjecting all samples to all substances in the round New Zealand is able to assess any farm based relationships or associations that may become apparent from the data.

2.3 Random monitoring & seasonal distribution

As stated above, a minimum of 322 random raw milk samples will be taken in 2008/09. All random raw milk sampling occurs at the farm bulk milk tank and as such is monitoring the conformance of the individual milk producers.

Dairy farming in New Zealand is pasture based and the milk production pattern is seasonal, following a similar curve to pasture production. Accordingly the NCCP operates on a July 1st to June 30th production year.

Figure 1 on the following page illustrates the milk supply curve across the dairy season, while figure 2 illustrates the cumulative milk produced as the season progresses, and is a sigmoid curve rather than a straight line.

93% of milk is produced between August 20th and April 30th each season, and accordingly the programme has historically applied all raw milk sampling through this period. Although a significant proportion of the milk supplied in the period May 1st to August 19th is for domestic consumption (as liquid milk and chilled dairy products), a proportional number of random supplies is be sampled over this period (i.e. 22 of the 322 random samples).

Figure 1: New Zealand Milk Supply Curve

Figure 2: Cumulative Milk Supply

2.4 Directed (targeted) surveillance

The surveillance component of the programme is designed to investigate and control the movement of dairy material deemed to be of higher risk based on the risk profile of the material for particular chemical hazards. Targeted sampling is undertaken on the basis of the risk associated with the compound, the existing level of management control, and the likelihood of non-compliance based on information available to NZFSA based on reports, non-compliances, audits and investigations. For 2008/09 targeted sampling will be directed to a minimum of 60 colostrum supplies taken at the farm or the tanker as this continues to be seen as an indicator for residue carryover from treatments and exposures that may have occurred over the dry period.

2.5 Determination of compounds to screen

As NCCP is risk based, the compounds to be analysed in the monitoring programme are dependent upon the risk profile for the particular compound and the most appropriate target compound, marker or metabolite for screening purposes. The compounds screened under the programme are subject to annual review.

Factors taken into account for any one compound include:

• toxicity of the compound;

• husbandry practices;

• extent and pattern of use of the chemical (risk prone times);

• exposure routes, including feed and environment;

• persistence in the environment (risk prone areas);

• previous monitoring frequencies and results ( across both NZFSA and industry programmes);

• availability of a practical regulatory analytical method;

• international concern about residues of the compound; and

• regulatory requirements of international markets.

3 Substances & Analytes for 2008/2009

The following sets out the rationale and consideration of high interest substances for inclusion in the 2008/09 dairy NCCP. Additional compounds of interest to New Zealand will be included based on the rationale set out under section 2.5. Lastly, further compounds are included when multi-residue screening methods are employed that are validated for a wider range the compounds.

The full list of substances to be included in the NCCP is provided in the following section. For 2008/2009 the programme will monitor more than 250 substances across a range of substance groups (refer to Table 2, section 3.3). Since 2000 the New Zealand programme has increased the average number of substances monitored almost 4 fold.

3.1 Group A: Substances having anabolic effect and unauthorised use

For monitoring of this class of substances please refer to the New Zealand’s National Chemical Residue Monitoring and Surveillance Programme for live and slaughtered animals.

The following substances are not deemed to represent a risk in New Zealand dairy material and as such are not included in the NCCP for 2008/09:

• A1 Stilbenes, stilbene derivatives, and their salts and esters;

• A2 Antithyroid agents;

• A3 Steroids;

• A4 Resorcyclic acid lactones including zeranol; and

• A5 Beta-agonists.

The New Zealand National Chemical Residue Monitoring and Surveillance Programme for live and slaughtered animals includes screening for trenbolone, stilbenes, steroidal substances and β-agonists.

A6: Compounds for which an MRL cannot be set

Chloramphenicol: there are currently no veterinary medicines containing chloramphenicol registered for use in New Zealand. Registration of chloramphenicol was withdrawn for food producing animals in 1988.

Use on dairy animals in New Zealand is therefore considered highly unlikely. Nevertheless, due to concerns about illegal use of the compound in other countries chloramphenicol has been included in the NCCP since its inception and will continue to be monitored in 2008/09.

Use of chloroform as an excipient in products was terminated in 2000/01. In the previous year all products were either reformulated to remove chloroform or the licence was cancelled. Chloroform will not be monitored by the NCCP for 2008/09 but may be included under random monitoring in the 2009/10 production year providing validated methodology is approved by NZFSA.

Chlorpromazine, colchicine and dapsone are not registered for use in New Zealand, and there are no indications for their use. Nevertheless, due to concerns about illegal use of the compound in other countries dapsone has been included in previous seasons and continues to be included in the NCCP for 2008/09, while chlorpromazine and colchicine may be included under random monitoring in the 2010/11 production year providing validated methodology is approved by NZFSA.

Dimetridazole is currently licensed for use in pigs and poultry under veterinary supervision. New Zealand’s extensive pasture-based husbandry practices would make its use in dairy cattle highly improbable. While not included in the NCCP for 2008/09, it may be included in the 2009/10 production year and reviewed thereafter to confirm the appropriate frequency for inclusion which has been tentatively set at one in every four years.

Metronidazole is currently exclusively licensed for the treatment of bacterial infections in cats and dogs. While not included in the NCCP for 2008/09, it may be included in the 2009/10 production year and reviewed thereafter to confirm the appropriate frequency for inclusion which has been tentatively set at one in every four years.

Nitrofurans: New Zealand has one nitrofuran with systemic absorption, licensed for use in food producing animals. Furazolidone is licensed for use as an oral formulation in pigs and poultry under veterinary supervision. Furazolidone is not approved for use in cattle, and New Zealand’s extensive pasture-based husbandry practices would make its use in dairy cattle very unlikely.

Nitrofurazone is licensed for use in ointments for non-food producing species (horses, small animals and ornamental fish). It is a legal requirement that products containing nitrofurazone are not be used on any animal producing or intended to produce food for human consumption, and this is stated clearly on the label of the medicine.

The registered products containing furazolidone and nitrofurazone are prescription veterinary medicines and a condition of registration is a specific direction prohibiting off-label use.

Nitrofurazone, furazolidone and furaltadone were included in the NCCP previously. However, due to international interest, analyses of the nitrofuran metabolites SEM, AOZ, AMOZ and AHD have been developed and validated for milk and included in the programme since 2004/05, and will continue to be monitored each production season.

While there is debate regarding the specificity of these metabolites (in particular semicarbazide which has been shown to be present from sources other than Nitrofurazone), analysis of these metabolites is considered to be more reliable than analysis for the parent drugs which are less stable. Because of the status of the nitrofurans (no registered use for dairy cattle) any detection of a metabolite in the absence of the parent drug will initiate immediate traceback procedures to determine whether any abuse has occurred. It is specifically noted that SEM will be used as a trigger for further investigation only.

Ronidazole has been licensed for use in New Zealand in cage birds. While not included in the NCCP for 2008/09, it may be included in the 2009/10 production year and reviewed thereafter to confirm the appropriate frequency for inclusion which has been tentatively set at one in every four years.

Aristolochia species and preparations containing these botanicals have no intentional use on milking animals and as such will not be monitored by the NCCP in 2008/09, but a small number of samples will be considered for inclusion under directed surveillance in 2010/11 providing validated methodology is approved by NZFSA.

3.2 Group B: Veterinary drugs and contaminants

B1 Antibacterial substances, including sulphonamides, quinolones

Cows in New Zealand are grazed outdoors on pasture all year round and not housed in feedlots nor fed concentrates at levels of significance. They are therefore not exposed to the same level or types of veterinary drugs that are associated with these more intensive husbandry practices.

The New Zealand national dairy herd has a relatively low level of mastitis, and when it occurs, treatment with antibiotics during lactation is only one of the control methods advocated in the “SAMM plan” (the seasonal approach to managing mastitis, published by the New Zealand National Mastitis Advisory Committee). Almost all mastitis antibiotics in New Zealand are prescription veterinary medicines and as such are under the control of the veterinary profession.

Dairy manufacturers maintain an intensive level of acceptance testing of raw milk. The Animal Products (Dairy) Approved Criteria for Farm Dairies requires risk management programme operators to test milk from each farm at least three times per month using an approved method such as the Delvotest “SP” Modified method. The action level for farm bulk milk supplies is the limit of detection of the test, 0.003 IU (1.8 ppb) sodium (or potassium) benzyl penicillin or equivalent per ml, a very stringent standard in comparison with others internationally.

With non-compliances, risk management programme operators are required to apply rigorous follow-up procedures, including farm traceback and financial penalties, and achieve a very high level of conformance based on the extensive testing across all operators. For 2008/09 the industry is expected to undertake some 1.2 million Inhibitory Substances tests on an approximate 2.8 million raw milk consignments (one in every 2.3 consignments).

In addition to this routine monitoring, the NCCP will, in 2008/09, screen milk supplies for evidence of penicillins, cephalosporins, aminoglycosides, macrolides, sulphonamides, tetracyclines and diamino pyrimidine derivatives.

B2(a) Anthelmintics: The NCCP will, in 2008/09, screen a proportion of milk supplies for evidence of benzimidazoles, levamisole, milbemycins and macrocyclic lactones.

B2(b) Anticoccidials, including nitroimidazoles: Due to the outdoor pastoral farming system in New Zealand dairy production, neither anticoccidial nor nitroimidazole compounds are indicated for use. Accordingly, they are not included in the 2008/09 NCCP.

B2(c) Carbamates and pyrethroids: The risk of contamination by synthetic pyrethroids in New Zealand milk is lowered due to the extensive grazing-based animal husbandry system. None the less, NCCP will continue to monitor milk supplies for evidence of synthetic pyrethroids.

Carbamates have been superseded by other remedies in New Zealand and are currently only registered for topical use in food producing species. However, New Zealand’s screening methodology for organophosphates is sensitive to these compounds and all non-identified responses are actively followed up. Additional surveillance samples for either group will be taken where considered appropriate.

B2(d) Sedatives: As the potential for these compounds to be present in milk is very low they are not included in the NCCP for 2008/09.

B2(e) Non-steroidal anti-inflammatory drugs (NSAIDs): The extensive nature of New Zealand’s farming systems, the expense of non-steroidal anti-inflammatory drugs relative to the value of the animals and their prescription veterinary medicine status, does not justify the common use of these products. None the less, NSAIDs have been included in the NCCP for a number of years and will continue to be monitored in 2008/09 with NCCP monitoring phenylbutazone, flunixin and ketoprofen.

B2(f) Other pharmacologically active substances:

Benomyl is used as a pasture spray to control the spores of the fungus pithomyces chartarum which, when consumed in high quantity by ruminants, result in liver damage and the condition “facial eczema”. These spores are only present when certain climatic conditions prevail. The surveillance component of the NCCP in 2008/09 may investigate the residues of benomyl in milk if weather conditions are such that there an increased facial eczema risk over past seasons.

B3(a) Organochlorine compounds including PCBs: Consistent with previous years, organochlorines will be included in the 2008/09 programme. This is primarily to continue monitoring the slow environmental decay of these compounds.

None of the 12 organochlorines that are currently part of the United Nations Environment Programme Persistent Organic Pollutants Programme have been registered or used in New Zealand for a number of years. The sales of dieldrin for use on food animals and or pasture was banned in 1967. In 1970, New Zealand became one of the first countries in the world to ban the use of DDT on pastoral land. However, the metabolites of DDT continue to be periodically identified in milk and milk products from livestock grazing land where DDT was historically applied to control “grass grub” (Costelytra zealandica). Residues of DDE, rather than the parent compound DDT, predominate confirming historic rather than recent use of this pesticide in New Zealand. NZFSA will continue to monitor areas where this compound was historically used. Farm dairy risk management programme operators are required to manage the risks under their programmes and, where necessary, to provide practical information on management techniques to minimise the uptake of the metabolites by milking animals.

New Zealand is not heavily industrialised and so the risk of dioxin or dioxin-like PCBs entering the milk supply is very low. This has been confirmed in historic surveys. None the less, surveys are undertaken periodically targeting farms deemed most likely to yield any level of detection. The last survey was undertaken in the 2006/2007 production year and a small number of targeted samples will be included in 2008/09.

B3(b) Organophosphorus compounds: Organophosphate compounds, as well as synthetic pyrethroids are included in the 2008/09 NCCP. These classes of compounds as licensed veterinary medicines are used primarily for ectoparasite control in food producing animals. Many organophosphates are very unlikely to occur as residues in New Zealand milk, because animal feeds, which may be treated with organophosphate insecticides are not used, and cows are not housed in barns which may require insecticide treatment.

The analytical method used in the programme uses internal standards of all organophosphates licensed for use in food producing animals. In addition the methodology will also identify any cholinesterase inhibitor, and further analytical steps can be employed to identify and quantify an organophosphorus compound which is not a licensed veterinary medicine.

B3(c) Chemical elements: Given the low level of industrialisation in New Zealand there is little heavy metal environmental contamination. As milking cows graze pasture and receive relatively minor quantities of feed from external sources, it is unlikely that contamination will occur through the feed supply.

In 2008/09 the NCCP will monitor raw milk for arsenic, boron, cadmium, lead, mercury, and selenium at the reduced frequency of 150 samples due to the historic absence of detections.

Dairy products that are manufactured using ingredients or additives that may contain metal residues greater than allowable limits are monitored for metal contamination under the appropriate Risk Management Programme.

B3(d) Mycotoxins: Aflatoxin M1 is derived from the intake of aflatoxin B1-contaminated feed by the milking animal. New Zealand pasture, conserved feed, grains and concentrates are very unlikely to contain aflatoxin-B1. Year-round suitable climatic conditions ensure that pasture grazing will continue to be the predominant feed supply for New Zealand dairy cows.

Conserved pasture, hay and silage are traditionally the most commonly supplied additional feed materials. These are harvested on each farm from surplus grass growth during the high growth periods in the spring and early summer (November to January).

Imported plant material such as palm kernel and, to a lesser extent, copra has increased over the last 4 years. Imported copra contaminated with aflatoxin B1 was identified in 2006 from NCCP raw milk screening and appropriate interventions put in place. Because of the growth in use of imported feeds the NCCP will continue to monitor for aflatoxin M1 in 2008/09 at a frequency of 172 samples (4 random monitoring rounds). Sampling will be directed to early and late in lactation when the proportional use of supplements is highest and per cow milk production is lower.

B3(e) Dyes: As these substances are of low risk they are not included in the NCCP for 2008/09.

B3(f) Others: New Zealand dairy products are routinely monitored for radionuclide contamination in conjunction with the national survey undertaken by the Ministry of Health National Radiation Laboratory. Monitoring includes Caesium-134 and Caesium-137, Strontium-90, Plutonium-239 and Americium-241. Additional radionuclide testing may also be undertaken according to the requirements of particular markets.

3.3 Substances and residues to be monitored in 2008/09

Table 2: Substances groups to be monitored in the year 1 July 2008 to 30 June 2009

(please refer to the NCCP Compounds List 2008/09 for the full list of chemicals covered)

Group of Substances	Compounds	Method	Farms to Sample
			Raw milk	Colostrum
Group A6
	Amphenicols	Elisa	322	30
	Dapsone	Microbial Inhibition	322	60
	Nitrofuran metabolites	LC-MS/MS	322	60
Group B(1)
Antibiotics	Penicillins	LC-MS/MS	72	60
		Microbial Inhibition	322	60
	Cephalosporins	LC-MS/MS	72	60
		Microbial Inhibition	322	60
	Aminoglycosides	Microbial Inhibition	322	60
	Macrolides	Microbial Inhibition	322	60
	Sulphonamides	Microbial Inhibition	322	60
	Tetracyclines	Microbial Inhibition	322	60
	Quinolones	Microbial Inhibition	322	60
	Miscellaneous	Microbial Inhibition	322	60
Antibacterials	Diamino pyrimidine derivatives	HPLC/Microbial Inhibition	322	60
Group B(2)(a)
Anthelminthics	Benzimidazoles	LC-MS/MS	322	30
	Imidazothiazoles	LC-MS/MS	322	30
	Macrocyclic lactones	HPLC-FL	122	30
Group B(2)(c)
	Synthetic pyrethroids	GCMS & GC-ECD	322	60
	Carbamates	GCMS & GC-ECD	322	60
Group B(2)(e)
	Non-steroidal anti-inflammatory drugs (NSAIDS)	GC-MS	172	30
Group B(2)(f)
Other pharmacologically active substances	Dexamethazone	GC-MS	50	30
Group B(3)(a)
	Organochlorines	GCMS & GC-ECD	322	60
	Acarides	GCMS & GC-ECD	322	60
	Fungicides	GCMS & GC-ECD	322	60
	Herbicides	GCMS & GC-ECD	322	60
Group B(3)(b)
	Organophosphates	GCMS & GC-ECD	322	60
Group B(3)(c)
	Basic Chemical elements	ICPMS	172	30
Group B(3)(d)
Mycotoxins	Aflatoxin M1	HPLC	122	0
		Elisa	50	0