Category "Environment"

Category "Science and Policy"

February 3, 2006

Global surface temperatures in 2005

Global surface temperatures in 2005

This is an image from NASA's Earth Observatory news site. The agency's Goddard Institute for Space Studies (GISS) considers 2005 to be tied for the warmest year ever recorded. The other year, 1998, was the year in which the strongest El Niño in a century occurred; 2005 reached the same high temperatures without an El Niño effect.

Here's what the GISS director has to say about 2005:


In early 2006, James Hansen, director of NASA GISS, pointed out that five of the warmest years over the last century were in the previous eight years: 1998, 2002, 2003, 2004, and 2005. Moreover, the GISS team states, “It is no longer correct to say that ‘most global warming occurred before 1940,’? an argument sometimes made by those who are skeptical of the link between human-produced greenhouse gases and global warming. Instead, the GISS team says, global warming over the last century up until 1975 was slow, with large fluctuations. Since 1975, there has been a “rapid warming of almost 0.2°C per decade.?

That's the same James Hansen who says he's being censored and hindered in his efforts to talk about global warming to the public. We can't screw around with this. This is a problem that transcends not only borders but time. And not just time in the sense of a few presidential administrations, but in the sense of generations.

Posted by rigd0003 at 10:27 AM | Environment | Science and Policy

Category "News"

Category "Public Health"

Category "Science and Policy"

January 25, 2006

Buying organic; BSE in the news


Illustration by Rafael Lopez

Consumer Reports recently produced a review of organic foods: Organic products: When buying organic pays (and doesn't). The investigators group foods according to how likely it is that a fruit, vegetable, or meat product contains pesticides and other additives. They also consider the price difference between organically- and conventionally-grown foods.

For example, CR suggests purchasing organic varieties of what the Environmental Working Group calls the "dirty dozen": apples, bell peppers, celery, cherries, imported grapes, nectarines, peaches, pears, potatoes, red raspberries, spinach, and strawberries. This is because these foods "consistently carry much higher levels of pesticide residue than others," based on USDA testing.

On the other hand, CR determined that purchasing organic seafood isn't worth it. The USDA has not established organic certification standards for seafood. And organically-produced fish can still contain mercury and PCBs.

It is important to point out that these evaluations are based solely on a comparison of certain contaminants -- what is typically seen on organic foods versus what is typically seen on non-organic foods. There is no consideration of environmental impact, animal production and handling practices, or other conditions that characterize organic farming. But CR does a good job of explaining why a certain organic food is deemed 'worth it' or not in their opinion. It's a good starting point for consumers to assess their own beliefs and value judgements in deciding whether to buy organic or not.

There was one part of the report that popped out at me as especially intriguing. For the most part, all the comparisons were an assessment of chemicals: pesticides, heavy metals, etc. There was no assessment of risks from infectious agents save one: BSE. CR suggests buying organic meat in part because of the reduced "risk of exposure to the agent believed to cause mad cow disease." They also mention that buying organic meat, poultry, and eggs is a good idea because of the antibiotics used in conventional farming and the greater potential for toxins in non-organic feed. I must say that worrying about contracting the human form of BSE, variant CJD, doesn't keep me up at night. But BSE and other prion diseases are definate health concerns.

The BSE point is especially interesting in light of Japan's recent re-instatement of U.S. beef ban just a month after it lifted its initial ban; and the continuing discovery of BSE in Canada, and suspected BSE in UK cattle born after the 1996 feed regulations.

There is interesting debate between Japan and the U.S. over what is considered risky for BSE. The risk of a cow getting BSE increases with age. This is because the BSE infectious agent, the prions, need time to become established in the brain and nervous system tissues and time to replicate and cause damage. (Find out more about BSE here.)

The U.S. argues that there is little or no risk of BSE in very young cows (less than 30 months old). Furthermore, the very small levels that would exist in these young cows would be too small to detect using the clinical tests that are presently available. These beliefs have resulted in two U.S. policy decisions: first, it is not useful to test any cows younger than 30 months old, and second, brain and other risky tissues pose no risk for transmitting BSE. Japan, on the other hand, tests all ages of cattle and prohibits risky tissues (also called specified risk materials or SRMs) from cows of any age to be included in any food product. This last difference is what prompted the ban reinstatement, and the difference is summarized nicely in this posting to ProMed-mail.

Personally, I tend to agree that testing of symptom-less cows less than 30 months old is futile with current technology. But I also think that the current feed bans for cattle in the U.S. are too permissive. I think they should read as the USDA organic standards do: "The producer of an organic operation must not feed mammalian or poultry slaughter by-products to mammals or poultry" (see National Organic Program regulation § 205.237 Livestock feed). I just don't want to eat meat from a herbivore animal that has been fed animal products. The organic rules aren't perfect, but they are a step in the right direction.

Posted by rigd0003 at 1:17 PM | News | Public Health | Science and Policy

Category "Me"

Category "PhD Process"

Category "Public Health"

Category "Science and Policy"

December 2, 2005

Outbreaks, Dissertation work, and Sprouts

An e-mail newsletter in my Inbox today contained links to two stories. The first story described a recent study by the Center for Science in the Public Interest concluding that produce contributed to more illnesses than poultry, eggs, and other animal products. CSPI studied reports of food-related outbreaks and noted the implicated foods that were the source of the disease-causing organisms.

This report comes at a very influential time in the food safety arena and it raises exactly the questions I am tackling in my dissertation work. There's a great interest in these types of attribution studies that seek to learn where foodborne illness cases are coming from. What types of foods are contributing most to the burden of disease?

But what we really want to know isn't just "what" but also "how" and "where." How are these foods becoming contaminated? Where in the food production, transportation, and preparation steps is this contamination occurring?

In outbreak investigations, the point of contamination can sometimes be difficult to discern. Produce may have been contaminated in preparation, often cross-contaminated from other foods in the kitchen. But there are increasing numbers of multi-state outbreaks where cases crop up in multiple places at about the same time. In these instances, it seems most likely that the implicated food was contaminated on the farm or during processing or shipping. This is where our ability to conduct trace-back investigations is key to solving the mystery of exactly where and how, and, hopefully, preventing similar contamination in the future. CSPI is lobbying for better record-keeping and ID tagging of foods to help in these efforts.

Another difficulty is lack of data. This study looked at outbreaks that had both an identified pathogen -- the bacteria, virus, toxin, or parasite was recovered -- and an identified source -- there was conclusive evidence that pointed to a food. But what about the unknown and unidentified? What about the people who become ill and never see a doctor and don't get tested? We don't have great data on the food side, either -- especially produce where no routine testing is done.

My work is to identify the first two of Sec. Donald Rumsfeld's information trilogy -- the known knowns, the known unknowns, and the unknown unknowns -- and give an account of where our knowledge lies in attributing Salmonella cases to foods at the point of production. [Secretary Rumsfeld got a lot of ribbing after that news briefing, but I've found his words very useful in my work and explaining my work to others!]

The other story in that e-mail relates more to a personal joke than the actual news item. The story is about a recent Salmonella outbreak in Ontario from mung bean sprouts. There have been several Salmonella outbreaks from various types of sprouts in the past decade or so. One of the difficulties in preventing these outbreaks is that Salmonella can contaminate the sprout seed itself, as well as during the growing phase.

The joke here is that I'd heard extensive accounts of these sprout-associated outbreaks from one of my major professors, Dr. Craig Hedberg. We'd worked closely on several food safety projects when I first arrived at the U of M. One time when we were on our way to a meeting off campus, we stopped for lunch at a little sandwich shop. I ordered the veggie special but told them to "hold the sprouts." Craig's eyebrow shot up, he gave a wry smile and said, "Don't do that on my account." I gave a snort and replied that if not on his account -- foodborne disease expert, veteran outbreak investigator -- than whose? And I'm not the only one. Our entire department, it seems, is sprout averse from Craig's stories. So, you see why I smiled when I saw that headline today. Craig is now over in Paris for a year, working with French officials on improving their foodborne disease surveillance. I have to wonder if he's sitting in a little French café at this moment, regaling his company with similar stories.

Posted by rigd0003 at 12:19 PM | Me | PhD Process | Public Health | Science and Policy

Category "Science and Policy"

August 25, 2005

Scientists engaging in public discourse

I've not posted in a while. I've been enjoying summer and doing a lot of reading - both for personal pleasure and professional progression.

Recently, I picked up the latest issue of Scientific American that had been sitting on my coffee table under a pile of other "to be read" material. The September issue (delivered in August, according to the special space-time and logic that dictates current magazine publication) is devoted to environmental sustainability and global problem-solving.

One of the things I most enjoy about SciAm is the opening Editorial, called "SA Perspectives," that sets the tone for the issue and makes scientific comment on current events. This month's Perspective particularly resonated with me. The editors encourage scientists to use their technical judgement to help society "navigate the shoals ahead." They acknowledge the danger of letting personal ideology steer research and narrow interpretation, but the greater danger is to disengage completely from public discourse.

Some critics, though, are unconcerned with philosophical debates about what scientists should or shouldn't do. Their complaints boil down to: I don't agree with what you're saying, and rather than engage with it, I will deny your legitimacy to say it. Sadly, that has become the dominant rhetorical strategy in the country today--one that will only make it that much harder to address the challenges of the coming decades.

I have seen this tactic often: scientists dismissed as talking heads. Sure, there are crack-pots and zealots in science. But unless we do something to change the current course, science will be marginalized as just another opinion and not as the beautiful tool for knowledge that it is.

Posted by rigd0003 at 11:39 AM | Science and Policy