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National Programme for Monitoring Chemical Contaminants and Residues in Raw Milk and

7 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 6.5. Lastly, further compounds are included when multi-residue screening methods are employed that are validated for a wider range the compounds.

The summary of substances to be included in the NCCP is provided in the section 7.6. For 2008/2009 the programme will monitor more than 250 substances across a range of substance groups. The full list of individual compounds and elements is provided on the NZFSA website at www.nzfsa.govt.nz/dairy

7.1 Melamine

This sampling plan has been reviewed and updated September/October 2008 in response to the melamine adulteration events reported from China, the subsequent review of toxicological data by various authorities internationally, and the acceptance thresholds implemented by NZFSA and others. The sampling plan now incorporates melamine in response to the current global interest in melamine when present in dairy products.

It should be noted that any adulteration of raw milk in New Zealand is prohibited. Testing under the NCCP has been introduced to confirm the safety and suitability of the national raw milk supply and the dairy products manufactured in New Zealand. A number of controls exist within the regulatory framework to ensure that adulteration or contamination of any kind does not occur. These include:

- Independent assessment of every farm dairy at least once per season as well as verification audits of all points from farm through to sale or export. This includes milk factories, stores, transport of milk or product, and milk transfer facilities.

- NZFSA specified raw milk acceptance criteria and raw milk monitoring for abnormalities, including the obligations on persons at the point of milk collection and milk delivery.

- Direct and exclusive contractual relationship between the farm and the processor with the processor owning the collection trucks. Rejected consignments and or farms under any form of sanction have no other disposal option so all farms have a very strong commercial incentive to meet both the processors and NZFSA’s qualitative parameters including freedom from all contaminants, SSC and microbial parameters.

- Existence of severe economic disincentives. In the event of any non-conforming level of any contaminant or mis-representation of raw milk severe penalties are applied by the milk recipients. In addition, prosecution procedures or other sanctions may be initiated by NZFSA for any illegal activity and NZFSA has wide ranging powers to legally direct that any milk or dairy product suspected to be affected be withdrawn or recalled from trade.

Analysis for melamine will be included in each raw milk round and on a minimum of 200 samples.

Laboratories recognised by NZFSA for the testing of milk and dairy products for melamine are identified under section 7.4.

7.2 Substances having anabolic effect or 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.

Nitrofurans: 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.

7.3 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). Use of maize in the form of maize silage to supplement pasture feeding continues to grow in popularity.

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.

7.4 NCCP laboratories

Laboratories testing samples from the NCCP are accredited to ISO 17025 – General Requirements for the Competence of Calibration and Testing Laboratories, by International Accreditation New Zealand (IANZ) for the analyses undertaken and, with the exception of HortResearch and the National Radiation Laboratory, are registered by NZFSA for the specific work required by the programme and use validated, NZFSA approved test methods. The HortResearch Laboratory and National Radiation Laboratory are recognised under the programme for their specialist capabilities. Table 2 provides the list of laboratories testing NCCP samples and the substances they test for.

Table 2: List of laboratories analysing NCCP samples

Laboratory	Substances
SAITL Dairy Laboratory (SAITL), South Auckland Independent Test Society Ltd P O Box 10 208 Hamilton	Antibacterial substances, including sulphomides, quinolones (Group B1) and baquiloprim.
Hort Research Ruakura Research Centre Horticulture and Food Research Institute of New Zealand P O Box 3123 Hamilton	Aflatoxins
AsureQuality Lynfield Laboratory 131 Boundary Road, Blockhouse Bay PO Box 41 Auckland	Chemical elements
National Radiation Laboratory Ministry of Health 108 Victoria St Christchurch	Radionuclides
AsureQuality Laboratory AsureQuality Ltd 1b Bell Road, Gracefield Lower Hutt	All remaining listed substances.

Melamine Analysis

In addition, the following NZFSA recognised laboratories have methods approved by NZFSA for the analysis of melamine in milk and dairy products. NZFSA have developed specifications to ensure that sample preparation and analyses are appropriate for all dairy sample matrices at the lower reporting limit, to ensure minimum laboratory analytical performance requirements are met, and to ensure the accuracy of reported results. In situations where detection requires quantitation below 1 mg/kg LC-MS/MS is the preferred confirmation procedure.

Table 3: List of laboratories recognised for melamine and cyanuric acid analysis

Laboratory	Instrumental Method
AsureQuality Ltd 1b Bell Road, Gracefield Lower Hutt www.asurequality.com	LC-MS/MS
RJ Hill Laboratories 1 Clyde Street Hamilton http://www.hill-laboratories.com	LC-MS/MS
SGS NZ Ltd 17 Maurice Road Penrose, Auckland www.nz.sgs.com	GCMS
Cawthron Institute 98 Halifax Street East Nelson http://www.cawthron.org.nz	HPLC screen LCMS confirmation

7.5 Interlaboratory Proficiency Testing

The laboratories in the NCCP are required to participate in proficiency testing programmes where these are available for the NCCP analyses undertaken.

7.6 Substances and residues to be monitored in 2008/09

Table 4: 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		Dairy
			Raw milk	Colostrum	Products
Group A6
	Amphenicols	Elisa	322	30	50
	Dapsone	Microbial Inhibition	322	60	50
	Nitrofuran metabolites	LC-MS/MS	322	60	50
Group B(1)
Antibiotics	Penicillins	LC-MS/MS	72	60	50
		Microbial Inhibition	322	60	50
	Cephalosporins	LC-MS/MS	72	60	50
		Microbial Inhibition	322	60	50
	Aminoglycosides	Microbial Inhibition	322	60	50
	Macrolides	Microbial Inhibition	322	60	50
	Sulphonamides	Microbial Inhibition	322	60	50
	Tetracyclines	Microbial Inhibition	322	60	50
	Quinolones	Microbial Inhibition	322	60	50
	Miscellaneous	Microbial Inhibition	322	60	50
Antibacterials	Diamino pyrimidine derivatives	HPLC/Microbial Inhibition	322	60	50
Group B(2)(a)
Anthelminthics	Benzimidazoles	LC-MS/MS	322	30	0
	Imidazothiazoles	LC-MS/MS	322	30	0
	Macrocyclic lactones	HPLC-FL	122	30	0
Group B(2)(c)
	Synthetic pyrethroids	GCMS & GC-ECD	322	60	50
	Carbamates	GCMS & GC-ECD	322	60	50
Group B(2)(e)
	Non-steroidal anti-inflammatory drugs (NSAIDS)	GC-MS	172	30	0
Group B(2)(f)
Other pharmacologically active substances	Dexamethazone	GC-MS	50	30	0
Group B(3)(a)
	Organochlorines	GCMS & GC-ECD	322	60	50
	Acarides	GCMS & GC-ECD	322	60	50
	Fungicides	GCMS & GC-ECD	322	60	50
	Herbicides	GCMS & GC-ECD	322	60	50
Group B(3)(b)
	Organophosphates	GCMS & GC-ECD	322	60	50
Group B(3)(c)
	Basic Chemical elements	ICPMS	172	30	50
Group B(3)(d)
Mycotoxins	Aflatoxin M1	HPLC	122	0	30
		Elisa	100	0	0
Group B(3)(f)
	Melamine	LC-MS/MS	322	0	200