Tuesday, March 10, 2015

Milk Safety in Maine in Context

We hear a lot of discussion these days about of food safety and the “dangers” of raw milk and the risks associated with a small, unregulated market, so let’s talk about safety.  Let’s consider three standards of measure.  First, the hazard, that is, what causes the harm; second, the risk, that is, what’s the probability the hazard will cause harm; and third, safety, that is, given the definition of the hazard and the probability that the hazard will cause harm, what’s an acceptable level of risk?

The hazards of consuming milk, raw and pasteurized, are real.  We know that a wide variety of germs that are sometimes found in milk and milk products can make people sick and sometimes die. 

In the United States the CDC’s foodborne disease outbreak database reports that from 1998 to present there have been 31 outbreaks from foodborne pathogens in pasteurized milk and solid cheese, representing 2940 total illnesses and 10 deaths.  Similarly, in the same period, there have been 136 outbreaks in raw milk and raw milk cheeses representing 2464 total illnesses and 2 deaths.1

Two illnesses were reported in Maine attributed to raw milk in home use but nether of these individuals required hospitalization, and this milk wasn’t traced to any farm or milk distributor. 

Using extrapolated data, another statistical analysis suggest that annual estimates of foodborne illnesses from dairy may be somewhat higher, but are recognized in the study as probably overstated because of methodology.2

By the way, there are other hazards associated with milk consumption that are often glossed over:  an increased risk of prostate 3-5 and breast cancers,6 insulin-dependent (or type 1) diabetes,7 food allergies, especially in children,8 and constipation in children.9 Children suffering from colic has even been linked to breastfeeding mothers’ consumption of cow’s milk.10 Now none of these hazards will be discussed here, but we should be aware that there are other health and safety risks to consider when we talk about food safety in the context of milk.

When we talk about risk, we’re talking about the chances someone will experience an adverse effect.    So let’s put the risk of illness and death from foodborne pathogens from all milk products, ignoring the other hazards associated with milk consumption, in context.

We can relatively simply consider the probabilities of death from consuming these items.  Let’s take the population of the United States over the period 1998 to the present, a little over 300 million souls.11 Using past data as a guide, the probability of becoming ill in any one year from a foodborne pathogen associated with milk, raw or pasteurized, is roughly 1 x 10^-6 which indicates an illness rate of about 1 in 1 million.  The probability of dying in any one year from dairy products is about
2.4 x 10^-8 which indicates a death rate of about 1 in 42 million.

Reflect on that for a moment.  Your odds of dying from consuming milk or milk products are about 1 in 42 million.  Even given an error of an order of magnitude, we can conclude these risks are small, given other risks we cheerfully assume.

So let’s compare these risks to risks from other common activities that we tolerate with little or no discussion. In 2013 alone, there were 8 deaths and 11,400 hospitalization treatments for non-occupational fireworks related injuries.12 The odds of becoming injured in such an accident are about 1 in 36,000 and dying in such an accident are roughly 1 in 37 million. 

Annually, 38,000 people require hospitalization from furniture and television tip overs, and in the 5 years from 2000 through 2014, there were 430 deaths, 360 of them children under 10 years of age.13 The odds of receiving such an injury are higher than 1 in 8,000, and the odds of dying from one of these accidents are about 1 in 3.5 million.

An average of 51 people perish from lightening strikes each year.14  The odds of dying from a lightening strike are roughly 1 in 5.9 million, and those are an order of magnitude higher than from consuming dairy products.14  In fact 3 unlucky individuals in Maine died from lightening strikes in the period 1998 to 2012 while none were lost to the consumption of dairy or dairy products.15

Consider, for comparison, that an estimate of 440,000 annual deaths from errors in care in hospitals is roughly one-sixth of all deaths that occur in the United States each year.  Your odds of dying from a treatment error in hospital are greater than 1 in 700.16

In this context, please realistically consider the risks associated with the consumption of raw and pasteurized milk and milk products.

Secondary to the discussion of statistical risk is the scale of possible adverse events.  If a small milk producer sells contaminated milk or milk products and his or her clients become ill, the potential scale of the outbreak, and consequently the number of people affected, is small. If a large milk distributor sells contaminated milk or dairy products, since the market and potentially infected population is larger, the consequences are far greater in terms of public health.  Or to use an analogous example by way of illustration, a farmer selling contaminated beef out of his or her freezer will affect far fewer people than the population affected by a 1.8 million pound ground beef recall, as we saw last year17. 

So now let’s talk about safety, that is, the acceptable level of risk.  The riskiest behavior any of us engage in is driving or riding in an automobile (with odds greater than 1 in 9000 of dying), yet we do it every day.18  We’ve recently legalized non-commercial fireworks in Maine, knowing the risks and trusting consumers to use them wisely and safely.  Most hotels secure their television sets to prevent tip overs, yet homeowners typically do not, assessing the hazard and risk and assuming responsibility for that decision themselves.  We still go to hospital when needing acute medical treatment, knowing that many preventable errors have high mortality rates there.

Individuals, knowing the hazards and assessing risks, make decisions about safety every day.  And they have the capacity to make decisions concerning the purchase of milk and milk products.

Knowing that we make decisions concerning safety every day, let’s turn to the inspection process.  There is no recent data that reveal that there have been any illnesses or deaths from small, uninspected farms in Maine. None.  

And do not think that regular purchases of unpasteurized milk and milk products from uninspected facilities do not occur and are not common.  These transactions do occur, and they are more common than many would like to admit.  In other words, the inspection process by which a patron purchases milk from an uninspected dairy, as evidenced by the apparent absence of illnesses and deaths, seems to be effective.

Ponder that for a moment.  Perhaps the relationship and inspection regime that exists between a farmer and his or her patron may be more effective in making sure the milk and milk products sold in this type of retail exchange are safe than the architectural and testing industry requirements that now prevail.

The consumption of milk and milk products does contain hazards.  The epidemiology of illnesses caused by foodborne pathogens is well known and well documented.  The risks associated with the consumption of these products are less well quantified, but obviously less than some would have us believe, certainly smaller than the risks many of us willingly assume every day. It’s important to determine the safety of these products and the efficacy of a face-to-face inspection model, vis à vis the architectural and testing model currently in place, with the best available data.

Let’s recognize patron inspection of dairy facilities as a legitimate inspection regimen and, given the lack of data to conclude otherwise, allow the sale of unregulated farm-produced dairy products at the site of production.  I can assure you that the sky won’t fall, rivers won’t turn to blood, and I don’t foresee dogs mating with cats any time soon.

2 Painter JA, Hoekstra RM, Ayers T, Tauxe RV, Braden CR, Angulo FJ, et al. Attribution of foodborne illnesses, hospitalizations, and deaths to food commodities by using outbreak data, United States, 1998–2008. Emerging Infectious Diseases 2013 Mar http://dx.doi.org/10.3201/eid1903.111866.  p. 411.

3Qin L, Xu J, Wang P, Tong J, Hoshi K. Milk consumption is a risk factor for prostate cancer in Western countries: evidence from cohort studies. Asia Pac J Clinical Nutrition. 2007;16:467–476.

4Song Y, Chavarro JE, Cao Y, et al. Whole milk intake is associated with prostate cancer-specific mortality among U.S. male physicians. Journal of Nutrition. 2013;143:189-196.

5Chan JM, Stampfer MJ, Ma J, Gann PH, Gaziano JM, Giovannucci E. Dairy products, calcium, and prostate cancer risk in the Physicians’ Health Study. American Journal of Clinical Nutrition. 2001;74:549-554.

6 Kroenke CH, Kwan ML, Sweeney C, Castillo A, Caan Bette J. High-and low-fat dairy intake, recurrence, and mortality after breast cancer diagnosis. Journal of the National Cancer Institute. 2013;105:616-623.

7 Saukkonen T, Virtanen SM, Karppinen M, et al. Significance of cow’s milk protein antibodies as risk factor for childhood IDDM: interaction with dietary cow’s milk intake and HLA-DQB1 genotype. Childhood Diabetes in Finland Study Group. Dibetologia. 1998;41:72–78.

8 Sampson HA. Food allergy. Part 1: immunopathogenesis and clinical disorders. Journal of Allergy and Clinical Immunology. 2004;113:805–819.

9 Iacono G, Cavataio F, Montalto G, et al. Intolerance of cow’s milk and chronic constipation in children. New England Journal of Medicine. 1998;339:1100–1104.

10 Paronen J, Bjorksten B, Hattevig G, Akerblom HK, Vaarala O. Effect of maternal diet during lactation on development of bovine insulin-binding antibodies in children at risk for allergy. Journal of Allergy and Clinical Immunology. 2000;106:302–306.

16 James, John T. A New, Evidence-based Estimate of Patient Harms Associated with Hospital Care. Journal of Patient Safety: September 2013 - Volume 9 - Issue 3 - p 122–128.



1 comment:

  1. And let's not forget the outbreaks of illess from spinach and cantaloupe. I don't see anyone prohibiting sales, backyard or otherwise, of those products.