Quality quarrel: Longstanding U.S. debate gets global pressure

Milk quality export paper trail would go all the way back to individual U.S. farms under EU requirements

By Dave Natzke

The U.S. dairy industry has gained some time to discuss and avert a potential disruption of some dairy product exports.

As Eastern DairyBusiness went to press this month, it was unclear how or when the United States would deal with new European Union (EU) dairy product export certificate requirements. Under those requirements, dairy products entering EU countries must be made from milk with less than 400,000 cells/milliliter (cells/ml), certified at the individual farm level. The EU has accepted dairy products made from commingled tankers or silos with less than 400,000 cells/ml since 1997.

The EU Food and Veterinary Office (FVO) announced the requirements in early April 2010, originally setting an Oct. 1, 2010 deadline. However, both the National Milk Producers Federation (NMPF) and U.S. Dairy Export Council (USDEC) asked the U.S. Food and Drug Administration (FDA) to intervene, saying requiring individual farm certification would create hardships for U.S. dairy farmers and processors. Furthermore, NMPF and USDEC said the 400,000 cells/ml standard raises both scientific and World Trade Organization trade questions.

EU and U.S. food and agriculture officials met in early July, agreeing to extend implementation of the revised SCC certificate program to Dec. 1, 2010. Even that, however, is a “soft” deadline, as the EU and U.S. work out details.

Current U.S. standard: 750,000

The current U.S. legal limit for bulk tank SCC, established under the Pasteurized Milk Ordinance, is 750,000 cells/ml. California’s legal SCC limit is 600,000 cells/ml.

By one measure, most U.S. dairy producers already meet the EU standards. Regional and seasonal variations exist, however. Based on latest Dairy Herd Improvement (DHI) herd records, SCC levels fluctuate by geography – presumably related to regional climate – as well as season and, to a lesser extent, herd size.

Somatic cell scores (SCS) of milk are reported to USDA’s Animal Improvement Programs Laboratory as part of an individual cow’s test-day yield information. The test-day data is reported annually for all herds (including owner-sampler herds) enrolled in DHI SCC testing (97% of all DHI herds in 2009).

The SCS are converted back to a milk SCC for calculating herd and state averages. Nationally, average test-day herd SCC during 2009 was 233,000 cells/ml, down 29,000 cells/ml from 2008. Most states (42) had lower average SCC than reported a year earlier; only six states had higher averages.

Somatic cell scores (SCS) of milk are reported to USDA’s Animal Improvement Programs Laboratory as part of an individual cow’s test-day yield information.

According to DHI test-day data:

• Highest average annual SCC levels were in Southeast states, where heat and humidity can combine to pose the biggest milk quality management challenges (see Table 1). Nine of the top 10 states with highest 2009 average test days greater than 400,000 cells/ml were in the Southeast. Three states in the region had annual herd test-day averages of more than 400,000 cells/ml for 2009: Alabama, Arkansas and Louisiana.

Although climatic conditions likely contributed to regional SCC differences, differences between adjacent states were substantial, suggesting herd size and mastitis-control practices, including genetic selection, impacted state differences as well, according to the report’s authors.

Based on latest Dairy Herd Improvement (DHI) herd records, SCC levels fluctuate by geography – presumably related to regional climate – as well as season and, to a lesser extent, herd size.

• As expected, the seasonal pattern for milk quality is shows the biggest challenges in April-July. The highest quality milk is produced in November and December (Table 2).

• Herds of 100 cows or less tended to have a greater number of test days above 400,000 cells/ml (see Table 2). Herds of <200 cows averaged more than 10% of all test days above 400,000 cells/ml.

• The United States has been making progress on lowering average SCC. Annual SCC for test herds averaged above 300,000 between 1995-2003, but fell to 233,000 in 2009. The decline from 2008-09 was the largest annual year-to-year decrease since the downward trend started in 2001-02 (Table 2).

Debate continues

The SCC discussion has been a national debate for at least two decades. The National Conference on Interstate Milk Shipments has tried – and failed – to lower U.S. SCC limits from the current 750,000 cells/ml on several occasions since the mid 1990s.

The argument often used against the lower limits – and one used by NMPF and USDEC against EU’s new requirements – is that SCC between 400,000-750,000 cells/ml do not pose a human health threat, especially since exported dairy products are from pasteurized milk.

In the letter to FDA commissioner Margaret Ann Hamburg, NMPF and USDEC contend the EU standard of 400,000 cells/ml for individual farms is “inappropriate,” and may be motivated more by trade issues than concerns over product quality or safety. Even within its own member countries, the EU enforces acceptance of milk that is “out of compliance” on an individual basis, and differently for products such as cheese aged more than 60 days, the letter states.

The letter states the U.S. dairy industry will discuss the feasibility of a revised EU certification program for SCC testing with FDA and the other relevant agencies, seeking a plan that is viable and non-burdensome for U.S. dairy producers, cooperatives and processors.

What impact on exports?

While the Southeast faces the largest SCC challenges, that area is not currently a major export supplier. USDA’s latest dairy export data shows just one Southeast state – Tennessee – recorded any dairy exports in 2009, and just two – Tennessee and Kentucky – were sources of dairy exports in the past decade. (USDA said about $548 million in dairy exports were “unallocated” in 2009, without a state designated as a source. USDA bases export share estimates on each state’s dairy product production, instead of using data from export shipping locations.)

We know, however, that milk moves much greater distances than in the past, and may move to other regions under federal order balancing. In addition, the EU requirements cover not just primary products, but also byproducts, such as whey. Several processors have already implemented standards meeting EU requirements.

Measurement differences

We’re all aware the U.S. measures length, weight and area using different units than the EU. Turns out there’s also a difference in how SCC is calculated,  too, noted Jeff Reneau, professor of dairy management at the University of Minnesota.

The EU uses the “geometric mean” a calculation made by taking the cube root of the three monthly SCC. In the U.S., the arithmetic mean calculation is normally used. According to Reneau, the geometric mean  reduces the influence of the occasional high SCC spike, yielding a lower number (Table 3).

Another question, Reneau said, is how monthly SCC will be determined. Fewer bulk tank SCC tests are done (bimonthly) in the EU than in the Upper Midwest, for example, where SCC tests are run on every pickup. Therefore, using the single “official” SCC test or some random selection of a single bulk tank SCC test done during any month would be comparable to what is done in the EU.

FYI

■ Read “Somatic cell counts of milk from Dairy Herd Improvement herds during 2009,” at http://aipl.arsusda.gov/publish/dhi/current/sccrpt.htm.

■ Visit the NMC (National Mastitis Council) website,  www.nmconline.org.

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