September 2009

It is long past time for meaningful changes in the safety of the food our children eat.  Whether the food is raw, local, organic, small farm, big farm, mass-produced or slow, if it contains E. coli O157:H7, or another pathogen, it can kill.  It can kill your child, grandchild or the child of a friend.  It can kill just like it killed Abby.  Here is her story:

E. coli Victim: Abby Fenstermaker from Marlerclark on Vimeo.

Abby’s illness, and her Grandfather’s, were linked to a Class I Recall by FSIS in May 2009 – Illinois Firm Recalls Ground Beef Products Due To Possible E. coli O157:H7 Contamination

Next week many consumers (several past and present clients) will be walking the hallowed halls of the Senate meeting with Senators and staff.  The goal is to make food safety real to those that have the opportunity to in part increase FDA funding, increase inspections of plants that manufacture our food (including foreign companies) and to increase the resources for the CDC to catch outbreaks earlier.

I will be delivering the Senators t-shirts with the following on them:

Whatever gets them to do the right thing is OK with me.

Lawsuit Seeks to Cover Millions In Medical Expenses

Victims of an August, 2008 outbreak of E. coli O111 have joined together to file suit against the Country Cottage restaurant, where they were sickened. The lawsuit was filed today in the District Court in the State of Oklahoma, in and for the County of Mayes, on behalf of twelve families.

“Many of us regularly entrust restaurants with our health and safety,” said the families’ attorney, William Marler. “There are stringent rules and regulations that restaurants must follow, because any deviation from those rules can cause illnesses. Sadly, this outbreak shows how very wrong things can go, and how much suffering can result.”

The outbreak at the Country Cottage Restaurant in Locust Grove, Oklahoma sickened 341 people, hospitalized 70, and caused the death of one man. Investigators quickly pinpointed the restaurant as the source of infection, but were unable to determine the specific vehicle. E. coli is often contracted by consuming food or beverage that has been contaminated by animal (especially cattle) manure. E. coli outbreaks have been tied to meat, produce, unpasteurized milk, cheese, and cider, sprouts, juice, and even water. The lawsuit cites the restaurant’s use of water from an unpermitted, on-site well just before the outbreak—in violation of Department of Environmental Quality (DEQ) regulations – as a basis for punitive damages.

“These fourteen people collectively spent 250 days in the hospital, 84 of them on dialysis for kidney failure,” continued Marler. “Their medical bills are almost two million dollars, not to mention ongoing medical care that many will continue to need. Our job is to make sure that they don’t struggle to carry that immense burden by themselves.”

Clostridium difficile (C. difficile) is a spore-forming, gram-positive anaerobic bacillus that produces two toxins: toxin A and toxin B. These toxins typically cause gastrointestinal disease, often with severe complications. In rare cases, C. difficile-associated disease can be fatal. Although C. difficile bacteria can be present in human intestinal tracts and cause no clinical symptoms (a condition called colonization), some individuals with C. difficile colonization are at increased risk of becoming ill. The most common risk factor for C. difficile-associated disease is exposure to antibiotics, especially those with broad-spectrum activity. Although less common, exposure to agents that suppress the immune system may also increase the risk of illness. Advanced age, severe underlying illness, gastrointestinal surgery, use of nasogastric tubes, and gastrointestinal medications (such as gastrointestinal stimulants or antacids) have also been associated with an increased risk of colonization. Most cases are acquired in hospitals or nursing homes, but an increased incidence of community–acquired C. difficile has been reported as well. Recent studies indicate that C. difficile can also be found in food products.  So, is it another bug to worry about in our food?  Visit C. difficile blog.

Parke Wilde keeps the U.S. Food Policy blog. He teaches graduate level courses in food policy and statistics at the Friedman School of Nutrition Science and Policy at Tufts University. In this list, he looked beyond the excellent sites that already appeared in a recent list at Culinate, which included Ethicurean, Green Fork, ChewsWise, Food Politics, Politics of the Plate, Grist, Civil Eats, and Obama Foodorama. Parke’s list adds some more blogs from within what might loosely be called the "good food movement," but it emphasizes other selections that he reads to maintain diversity in his information stream.

10 Excellent Food Policy BlogsMarler Blog – Commentary on food poising outbreaks and litigation.

Over at E. sakazakii blog there is a discussion of the naming and renaming of this very nasty bug.

Whatever the name it is a rare, but life-threatening cause of neonatal meningitis, sepsis, and necrotizing enterocolitis. In general, E. or C. sakazaii kills 40-80% of infected newborns diagnosed with this type of severe infection. E. or C. sakazakii meningitis may lead to cerebral abscess or infarction with cyst formation and severe neurologic impairment. E. or C. sakazakii can cause a variety of infections, though central nervous system infection has been most commonly described. For infants, infection typically manifests through signs of sepsis in the first week of life: irritability or lethargy, temperature instability, and feeding intolerance. Meningitis often produces overwhelming infection that rapidly moves through cerebral hemorrhage, infarct, necrosis, liquefaction, and eventually, cyst formation.

E. or C. sakazakii invasive infections occur more frequently in infants than in older children. The neonate’s immature immune system may increase the risk of acquiring an E. or C. sakazakii infection. In a study of E. or C. sakazakii cases over a 47-year period, investigators found that the median age at infection onset was two days and 94% of cases were less than 28 days old.

While the reservoir for E. or C. sakazakii is unknown in many cases, a growing number of reports have established powdered infant formula as the source and vehicle of infection. In several investigations of outbreaks of E. or C. sakazakii infection that occurred among neonates in neonatal intensive care units, investigators were able to show both statistical and microbiological association between infection and powdered infant formula consumption.

On September 25, 2009, I posted Part 1 of a 4-part series that examines the food safety record of both pasteurized and raw dairy products. Below is Part 2, which provides background on the occurrence of foodborne pathogens in milk products, and mechanisms of contamination.

Occurrence of Foodborne Pathogens in Milk and the Dairy Environment

Dairy animals such as cattle and goats may carry foodborne pathogens (e.g., Campylobacter, E. coli O157:H7, Listeria monocytogenes, Salmonella; see “cons” for a more extensive list). Often cows and goats that harbor foodborne pathogens in their gastrointestinal tracts do not appear to be ill. Occasionally, some of these bacteria cause mastitis (infection and inflammation of the udder), and may be shed directly into the milk. Certain strains of Salmonella and Listeria monocytogenes can cause serious systemic illness in ruminants. For example, Salmonella Dublin is a strain that is host adapted to cattle, and can lead to severe diarrhea and death in both cattle (especially calves) and humans.

Several authors have conducted extensive surveys of foodborne pathogens in bulk tank raw milk (BTM) and the dairy environment (Hancock et al 1998; Jayarao et al, 2006; LeJeune et al, 2009; Oliver et al, 2005; Oliver et al, 2005; Shere et al, 1998). BTM is milk from multiple cows mixed and stored in a container. Modern conventional dairies usually ship their milk in tanker trucks off-site for pasteurization. Milk from multiple farms may be mixed together. The majority of milk produced for pasteurization comes from confined animal feeding operations (CAFOs). In contrast, most commercial raw milk produced for human consumption in the US comes from pasture-based management systems as promoted by the Weston A. Price Foundation (WAPF). Milk from multiple cows may be mixed together and stored in a container, but raw milk from multiple farms is not usually combined. An exception would be “outsourcing” where the dairyman purchases additional milk from surrounding dairies to meet supply needs. This practice is probably uncommon, but considered dangerous because outsourced milk is not produced as required for the Grade A raw milk designation.

The most recent review of the literature on foodborne pathogens in BTM was published by Oliver et al (2009). The range in prevalence for BTM was summarized as follows:

Campylobacter: 2 – 9.2%
E. coli O157:H7: 0 – 0.75%
Listeria monocytogenes: 2.8 – 7.0%
Salmonella spp: 0 – 11%
Shiga-toxin E. coli: 2.4 – 3.96%
Yersinia enterocolitica: 1.2 – 6.1%

WAPF has raised a valid concern about using these surveys when assessing the occurrence of foodborne pathogens in commercial raw milk (e.g., raw milk sold legally on- or off-farm in the US). Because the BTM tested in these surveys was likely destined for pasteurization, the data does not specifically address the microbial quality or pathogen prevalence in Grade A raw milk sold for human consumption. Additional research is needed that compares BTM samples from licensed raw milk dairies to BTM intended for pasteurization. Furthermore, to fully understand the risk of pathogen contamination in raw milk being purchased and consumed in the US, surveys are needed that examine the prevalence of foodborne pathogens in raw milk produced by licensed, inspected raw dairies; unlicensed, “black market” raw dairies; and raw dairies selling their products as “pet food.”

Raw Bovine Colostrum

Colostrum is the “first milk” produced by the mammary gland of an animal after giving birth. Consumption of raw bovine colostrum appears to be increasing in popularity among raw milk drinkers, and has been associated with two recent foodborne disease outbreaks in California (CDC 2008; CDPH 2008). Unlike raw milk, raw bovine colostrum is regulated as a nutritional supplement. A recent survey of dairies in Pennsylvania by Houser et al (2008) found Salmonella in 15% of the colostrum samples; the mean standard plate counts (SPC) and coliforms were very high: 977,539 CFU/ml and 323,372 CFU/ml, respectively (see Oliver et al, 2009, for a broader discussion of sanitation standards). It was not specified in the paper if these dairies surveyed in Pennsylvania sold raw bovine colostrum for human consumption. Additional surveys are needed to study foodborne pathogens and sanitary standards in raw bovine colostrum from dairies that market the product as a nutritional supplement for humans.

Addressing the WAPF Claim: “Clean Grass Fed Cows” are Safe

WAPF and their Chapter members strongly promote the idea to their customers that raw milk is safe if produced by “clean grass fed cows.” Yet, the organization does not provide any survey data to support these claims. The only studies that potentially relate are found in the literature on grass vs. grain feeding and prevalence of E. coli O157:H7. This topic was reviewed previously. Briefly, the scientific evidence at this time does not support a broad conclusion that grass feeding significantly and consistently reduces the risk of E. coli O157:H7 or other dangerous foodborne pathogens from entering the food chain. More importantly, none of the surveys or experiments that WAPF cites examined raw milk operations, and instead focused primarily on dietary effects for cattle in feedlot conditions.

Most of the data on foodborne pathogen occurrence in the raw milk dairy environment comes from outbreak investigation reports. There are several examples where foodborne pathogens were found in the milk, cattle feces, and/or milking barn at dairies that follow WAPF principles including pasture-based, grass only feeding. In 2005, Washington state investigated an outbreak of E. coli O157:H7 linked to a cow-share, and found the outbreak strain in raw milk and environmental samples at the dairy (CDC 2007). In 2006, retail raw milk and colostrum were implicated in an outbreak of E. coli O157:H7 among children in California (CDC 2008). The outbreak strain was not found on the farm, but E. coli O157:H7 was present in the herd. In 2007, Campylobacter jejuni was isolated from 35% of fecal samples from cows at that same dairy in California; the outbreak strain was found in 4 fecal samples from those cows (CDPH 2008).

Addressing the WAPF Claim: Raw Milk Kills Pathogens

Another unsubstantiated claim by WAPF relates to the idea that raw milk is safe because the “good” bacteria and specific components in the unheated milk will destroy pathogens. A comprehensive review of this topic is beyond the scope of this paper. Briefly, the evidence that WAPF uses to promote this claim comes primarily from a paper by Doyle and Roman (1982) where Campylobacter jejuni was found to die-off at a more rapid rate in raw milk compared with sterile milk. However, the number of C. jejuni organisms in raw milk did not drop to a level below the infectious dose until about 7 days after inoculation. Furthermore, most C. jejuni stains also died-off in sterile milk, but not until a couple days later. WAPF does not make this distinction when promoting the safety of raw milk. Another consideration not addressed adequately by WAPF in their claims about raw milk safety is the importance of temperature abuse. Both raw and pasteurized milk are rich in nutrients, and if stored above refrigeration temperatures, can serve as an excellent medium for growth of pathogens (Wang et al, 1997).

A more extensive discussion on competitive exclusion and consumer perceptions was recently published by Rose (2009) as a White Paper.

How is Milk Contaminated with Pathogens?

There are 3 important points to consider about how milk becomes contaminated:

1. The initial mechanisms for raw milk contamination with pathogens are the same whether the milk is destined to be consumed raw, or pasteurized:

• Mastitis and shedding of the pathogen directly from the cow’s udder into the milk
• Entry of manure or dirt into the milk during the milking process
• Transfer of pathogens by vectors if they come in contact with the raw milk (for example, flies may carry pathogens on their legs and mouthparts)
• Human carriers transferring pathogens from their hands to the milk

2. The major difference between raw and pasteurized milk is the fact that the heat treatment during pasteurization destroys pathogens that may have entered the raw milk as described above.

3. Both raw and pasteurized milk can be contaminated during bottling, shipment, and storage. Pasteurization only destroys the pathogens in the milk at the time of processing; if unsanitary conditions allow pathogens to re-enter the milk later, it will be contaminated again.

There are two general causes of contamination of pasteurized milk:

1. Equipment failure: The pasteurization equipment fails and there is raw milk in the product sold as pasteurized. This can happen if the temperature is not high enough, or if the milk is not heated long enough. For example, in 1984, an outbreak of Salmonella Typhimurium occurred in a convent in western Kentucky (CDC, 1984). There were 16 illnesses and one patient developed a Guillain-Barre-type illness. The convent had a steam pasteurizer and investigators believe that the temperature may not have been high enough and/or the holding time was too short. The convent had no time-temperature gauge to record and monitor the process.

2. Post-pasteurization contamination: the milk is contaminated after pasteurization, usually through unsanitary handling of the milk. An example of post-pasteurization contamination involving a multi-drug resistant strain of Salmonella Typhimurium occurred in Pennsylvania and New Jersey in 2000 (Olsen et al, 2004). There were 93 illnesses and at least 6 hospitalizations. No Salmonella was isolated from the milk, but investigators concluded that the milk was most likely contaminated after pasteurization due to unsanitary conditions at the processing plant. For example, high humidity and excessive condensation in the plant could have produced droplets carrying Salmonella that fell into open containers of the pasteurized milk.

In the Age of Bioterrorism

Intentional contamination of the food supply through a bioterror attack has become an increasing concern. Wein and Liu published a provocative paper in 2005, where they modeled the vulnerability of pasteurized milk though the farm-to-consumer supply chain using botulinum toxin. They considered milk a possible target because of its symbolic value in society. The authors concluded that due to the rapid distribution and consumption of milk, an attack could result in several hundred thousand individuals poisoned with botulinum toxin.

It is worth noting that the conventional pasteurized milk supply is far more vulnerable to a massive poisoning compared with today’s raw milk supply. Several enormous, natural foodborne disease outbreaks involving pasteurized dairy products illustrate this point (Ryan et al, 1987; Hennessy et al, 1996). However, recent petitions to FDA to expand the raw milk supply chain by lifting the interstate ban on shipment could potentially increase the vulnerability of raw milk to larger outbreaks because a single contaminated lot would be consumed by many more individuals across a wider geographic area.

“Good” vs. “Bad” Bacteria: Probiotics and Dairy Products

One of the major concerns expressed by WAPF and other raw milk advocacy groups is that heat treatment by pasteurization destroys “good bacteria,” as well as pathogens. An example of “good” bacteria would be probiotics. A simple definition of a probiotic is a live microorganism (such as Bifidobacteria and Lactobacilli) that is beneficial to health when consumed. An example of a benefit from probiotics would be improved digestion.

Although raw milk may contain “good bacteria,” it is debatable whether raw dairy products fit the scientific definition of a probiotic food (see my previous review on Raw Milk Pros). Animals do not excrete “good bacteria” in their milk (usually milk is sterile when it exits the mammary gland). Both “good” and “bad” bacteria enter milk by the same mechanisms as described above. Sanitation during milking and processing at a raw milk dairy to prevent pathogens from entering the milk will very likely also lower the levels of probiotic bacteria. The ultimate question for the consumer is whether the trade off is worth the risk. It is worth noting that there is very little research on this topic. For example, studies are needed to measure the species and concentration of “good” bacteria in commercial raw dairy products to determine if they are sufficient to confer a probiotic effect.

In recent years, pasteurized dairy products containing probiotic bacteria have become increasingly popular. Products such as Activia® and DanActive® contain specific species and numbers of live probiotic microorganisms that are added to the dairy product after pasteurization to kill harmful bacteria.

The next segment of this review will compare foodborne illnesses and disease outbreaks linked to raw and pasteurized dairy products.

References

Continue Reading Comparing the Food Safety Record of Pasteurized and Raw Milk Products – Part 2

Tennessee Lawyer John Day is a reader of Food Safety News.

Food Safety News is a new publication sponsored by food safety expert Bill Marler and his firm Marler Clark. It contains information on the food safety issues of the day, whether they pertain to foodborne illness outbreaks, recalled products, or food politics. The online newspaper has bureaus in Seattle, Denver, and Washington, DC and has invited contributors from government, industry, academia, and consumer groups to share their viewpoints on food safety-related issues.

Blogs With Bite, by Mike Licht – Blogs with Bite is an occasional omnivorous sampling of food blogs and sites we find particularly tasty. Follow the trail of bread crumbs back to earlier editions, starting here:

Food Safety News — Comprehensive “daily Web-based newspaper … reporting on issues surrounding food safety.” Presented by Marler Clark LLP, PS, a law firm “dedicated to representing victims of food poisoning.”