Your all-time favourites

I have just reviewed the most common search terms resulting in visits to this blog.

By far the most common has been "Coliforms in food".  This has been a regular search since I started writing Safe Food in 2006, but has perhaps appeared more frequently since the Escherichia coli O104:H4 outbreak in Europe.

Coliforms are used as "indicator organisms" to show whether the food has been processed under hygienic conditions.  Presence of these bacteria mean that the food has potentially been contaminated with faecal material and hence faecal organisms, but to confirm this, we look for Escherichia coli presence in the food.

Surprisingly, the next most common search has been "Safety of Probiotics".  Probiotic bacteria are those that confer some benefit on the host.  Thus many foods, such as yoghurt, contain live bacteria that may colonise the gut of the consumer and confer some benefit.  These bacteria are often lactic acid bacteria.  Many claims have been made for the benefits of consumption, though there are some indications that administration to critically ill patients with acute pancreatitis may have deleterious effects.  There is also some evidence that administration to infants under 6 months of age may render them more prone to development of sensitivity to allergens.  For the majority of consumers, however, probiotics will not be hazardous and may be beneficial.

Do not confuse probiotics with "prebiotics".   These were so named by Marcel Roberfroid in 1995, who later wrote the definition: "A prebiotic is a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-being and health."  A major class of prebiotic is soluble fibre.

Much lower down the list are "Listeria in vegetables" and "Safety of chicken".  There has been a small spike in Listeria searches, probably as a result of recent recalls and the cantaloupe outbreak in USA that has killed approximately 29 people.  The incidence of listeriosis is very low and victims are usually neonates, the elderly and those people with compromised immune systems, but this outbreak seems to have been particularly dangerous.  Chicken has made regular appearances in the news, either being a vehicle for Salmonella or Campylobacter.  The incidence of Campylobacter infections in New Zealand has dropped significantly since the introduction of more stringent controls and biosecurity systems.

One new search now appearing is a bit disturbing: "Will eating spoiled food make you sick?".  I have previously written on this after receiving a direct question from a reader.  Is the increased interest a result of hardship in the community, or merely a thirst for knowledge?  I hope it is the latter.

Time to ban antibiotic use in animal husbandry?

As a microbiologist, I sometimes worry that we are killing the golden goose in terms of our ability to combat human disease.  As I wrote earlier, the cost of developing and bringing to market new drugs is astronomical and many companies are shunning new drug development in favour of more lucrative endeavours, such as development of molecular-based test kits for human disease diagnosis.

In this light, it is disturbing to read of the amount of antibiotics used in animal production.  In 2001, Kristin Leutwyler wrote in Scientific American that a study by the Union for Concerned
Scientists had shown meat producers in the USA feed around 25 million pounds of antibiotics to chickens, pigs and cows for non-therapeutic purposes each year (the antibiotics suppress microbial populations and lead to increased growth rates of the animals).  Compared with this, only 3 million pounds per year are used for treating human disease.

In 2009, the House Committee on Rules held a hearing: H.R. 1549 - Preservation of Antibiotics for Medical Treatment Act of 2009, which would have amended the Federal Food, Drug, and Cosmetic Act to require the Secretary of Health and Human Services to deny an application for a new animal drug that is a "critical antimicrobial animal drug" (CAAD) unless the applicant demonstrated a reasonable certainty of no harm to human health due to the development of antimicrobial resistance attributable to the non-therapeutic use of the drug.

The CAAD is a drug intended for use in food-producing animals that contains specified antibiotics, or other drugs used in humans to treat or prevent disease or infection caused by microorganisms. The Rule would also require the Secretary to withdraw approval of a non-therapeutic use of such drugs in food-producing animals two years after the date of enactment of the Act unless certain safety requirements are met.

That rule died in Committee.  It has been reintroduced in the 2011-2012 Congress, and went to Committee on 9th March, 2011. 

It has been argued that there are no good studies linking antibiotic use in animal rearing to the development of antibiotic-resistant diseases.

While this may be so, and I'm not sure that it is, it is hard to imagine how else multiple antibiotic resistant strains of bacteria could be found in animals and ultimately in humans.  A classic experiment shown to most undergraduate students of microbiology over the last 50 years is the selection of antibiotic-resistant bacteria.  All that is required is the production of a concentration gradient of antibiotic across a Petri dish.  The agar is seeded with the target bacteria and those that grow at the most concentrated side are picked off and recultured on another gradient.  Very quickly, a resistant strain can be isolated.

This laboratory procedure is effectively repeated in animals fed sub-therapeutic levels of antibiotics in their diet or drinking water - the survivors of the first dose are constantly exposed and eventually dominate the population.  As microorganisms transfer genetic information among themselves, the number of different strains resistant to the antibiotics also increases.

I would be less concerned if the antibiotics used for treating animals were no longer in use for human therapy.  Then the benefits could perhaps be justified, though even then, the class of antibiotic is important, as bacteria becoming resistant to one member of the class might also develop resistance to others.  If humans become infected by strains resistant to antibiotics used in human therapy, there may be no cure available for the infection.  These infections could easily be transferred by handling raw meats from treated animals, though there is again a lack of sound scientific evidence.

The view is clouded by the indiscriminate use of antibiotics by humans.  It's not just a case of doctors prescribing antibiotics when they are not justified, though I have seen antibiotics prescribed for viral diseases, which generally can't be treated with these chemicals.  Look up "availability of antibiotics over the counter" and you will get pages telling you that there is none.  However, it is well known that antibiotics can be bought freely over the counter in some countries.  Even the antibiotics of last resort - the only ones that can treat certain diseases - can be bought in pharmacies in some Asian countries and there are papers in the scientific literature showing the levels of resistance in bacterial populations.

I truly hope that President Obama eventually signs this legislation and that leaders of other countries do likewise.  I would hate for us to descend to the state before the introduction of penicillin, when even a scratch from a rose thorn could result in painful death.

Those dreadful scientists - do they ever do any good?

 If you read the popular press, you could be excused for thinking that scientists, particularly the genetic engineers, are a pretty bad bunch.  Wandering round spooky laboratories wearing white coats, these bearded boffins invented preservatives that are now widely used in processed foods, they developed milk pasteurisation and homogenisation, and the genetic engineers made corn with built-in insecticide.  Food technologists are employed by food manufacturers to make food keep forever and fool the consumers.

My perhaps somewhat biased view is that this is absolute rubbish.  To name just a few good things, we have safe food and effective vaccines, a whole range of new fruit cultivars and wonderful test kits that can quickly diagnose all kinds of disease.  All these things were developed by scientists, technologists and engineers.

A recent report from Cornell University describes a new test to trace and identify outbreaks of foodborne disease.  So far this is applied only to a common Salmonella subspecies, but the principle can be applied to many other foodborne disease bacteria.

One way of recognising a specific bacterial strain, such as one suspected of causing a food poisoning outbreak, is to chop up the DNA into bits with enzymes and to amplify the bits, followed by separation of the fragments by gel electrophoresis, which is a way of creating a band pattern or fingerprint.  Alternatively, parts of the DNA can be amplified with random primers, or starting sequences, that will also produce a fingerprint.  You will have seen DNA fingerprints used for crime detection in various television series.  However, it is never as quick and simple as portrayed in these cop shows.  Unfortunately, closely related bacteria may produce band patterns that can't be distinguished, making it impossible to differentiate one strain from another.

With the development of very rapid sequencing techniques, it is now possible to determine the nucleotide sequence of the full bacterial genome.  In other words, we can read the whole genetic code of the bacterium.  Very closely related strains may differ by only a few nucleotides, or code letters.  By looking at these very small differences, we can tell if a particular strain was responsible for apparently linked illnesses in Germany, United Kingdom, New York, and France.  The technique is called Single Nucleotide Polymorphism (SNP) test.

The technique is still quite expensive, but as rapid sequencing is developed further, the cost is likely to decrease.  Being able to track an infecting bacterium, such as the Escherichia coli that caused so much disease and death in Europe earlier this year, is a valuable tool in fighting such outbreaks.  In the face of such devastating outbreaks of foodborne disease, the cost of full sequencing is insignificant.

The researchers, led by Martin Wiedmann, who developed the technique intend to continue perfecting the method and to apply it to other bacteria.


Of course, the description above is a gross simplification of the SNP test.  Wiedmann's original paper is highly technical.  You can read it in:
Applied and Environmental Microbiology, 2011; DOI: 10.1128/AEM.06538-11

Alternatively, you can read a press release from Cornell University at:
http://www.sciencedaily.com/releases/2011/10/111025113540.htm#.TqoxsV5BB1U.email

Food Safe Families: Does it Prevent Contamination of Foods? Guest Editorial

Patricia Walling^*

In just about any news medium, headlines about recalls of meat, poultry and produce due to contamination occur with deadly regularity. Sadly as anyone in health care knows these headlines aren't just hype; food borne diseases can be fatal. This is especially true when they infect the very young, elderly and those with compromised immune systems.

According to the Center for Disease Control and Prevention (CDC) “each year, 1 in 6 Americans, or 48 million people get sick, 128,000 are hospitalized and 3,000 die of food borne diseases.” The agency notes that among the 31 known food borne pathogens, the leading causes of deaths and hospitalization are: Salmonella, Toxoplasma, Listeria, norovirus and Campylobacter.

Based on this public health problem, a partnership was formed among several U.S. governmental agencies (including the U.S. Department of Agriculture, the Department of Health and Human Services, the Food Safety and Inspection Service, Food and Drug Administration and the CDC) that are charged with keeping the food sources safe in conjunction with the Ad Council. The campaign, recently announced by the USDA, is titled “Food Safe Families.”

These organizations feel that this promotional effort will “shift the way people think about food handling so they can take a more proactive approach at home to help reduce food-related illnesses.” However, not everyone feels this educational and health promotion campaign will do much to solve the real challenges of the food distribution system.

The Food Safe Families Program

Public service campaigns, created by U.S. governmental agencies have a storied history. From the iconic U.S. Forest Service and Ad Council campaign that featured Smokey Bear admonishing that: “Only you can prevent forest fires” (launched in 1947), to the FDA’s “Food Pyramid” (first launched in 1992, updated in 2005 and then replaced in 2011), there have been hundreds of public service campaigns that are well-meaning but often ineffective.

Will the Food Safe Families campaign have the promotional “legs” of Smokey Bear’s message or join “Just Say No” campaign as a waste of taxpayer money? Only time will tell. However, the campaign includes several aspects that make it important.

According to the USDA Food Blog, “using the motto “Check Your Steps,” Food Safe Families aims to get consumers to adopt four very easy steps when preparing food:

1. Clean: Clean kitchen surfaces, utensils and hands with soap and water when preparing food.

2. Separate: Separate raw meats from other foods by using different cutting boards.

3. Cook: Cook foods to the right temperature by using a food thermometer.

4. Chill: Chill raw and prepared foods promptly.”

These four steps – clean, separate, cook and chill – serve as the graphic and messaging platform of the campaign. The agencies hope that by constantly reiterating this message, it will become ingrained in those who are charged with preparing the family meals.

Even the timing of the launch was important. The agencies choose Jun. 28, 2011, because this is the start of summer and represents the prime outdoor grilling season for most families. The USDA noted in its blog that “food borne illnesses tend increase with more outdoor meals.”

Once the campaign was launched, it seemed that Food Safe Families had covered most of the promotional bases. There were spiffy new graphics, memorable message points, an innovative social media campaign and public service media all up and running. The timing and execution of the campaign was excellent, until people started showing up in emergency rooms with symptoms of Listeriosis.

The Listeria Outbreak

Jensen Farms, located in Holly, Colorado grows and ships cantaloupes throughout the United States. After numerous reports of an outbreak of Listeriosis, the FDA and CDC traced the contaminated melons back to this farm. According to a news update from the FDA on Sept. 30, 2011, “the cantaloupes were produced from the end of July to Sept. 10, 2011. Given that the Jensen Farms’ recall has been in effect for more than two weeks, it is expected that all of the recalled whole Jensen Farms cantaloupes have been removed from the marketplace.”

The website for the Mayo Clinic notes that “Listeria infection is a food-borne illness that can be very serious for pregnant women and people with impaired immune systems. Listeria bacteria can survive refrigeration and even freezing.” As of Oct. 1, 2011, the CDC reported that the contamination had been responsible for the deaths of 17 people and the illness of 84 across 19 states.

In response to this outbreak, the FDA noted that “It is very important that consumers clean their refrigerators and other food preparation surfaces. Consumers should follow these simple steps:

• Wash hands with warm water and soap for at least 20 seconds before and after handling food.

• Wash the inside walls and shelves of the refrigerator, as well as cutting boards and countertops.

• Wipe up spills in the refrigerator immediately and clean the refrigerator regularly.

• Always wash hands with warm water and soap following the cleaning and sanitization process.”

Do These Guidelines Prevent Food Borne Illness?

For all of the regulations, safeguards, inspections and, yes, public service campaigns, the growers and processors of food employ humans and sometimes they get careless and make mistakes. Such is also the case with homemakers.

In cases where these mistakes cause deadly diseases to spread, the Food Safe Families campaign could help to ameliorate the damages from contaminated cantaloupes, ground meat, peanut butter or any other food. However, it will have no effect on preventing the disease from starting. That involves many other factors. These include: the distance and the number of companies that must handle food between the farm and family and the quantity and quality of the inspections along the distribution channels.

Given time, the Food Safe Families campaign could have a positive impact on the health of U.S. citizens. Even now, the use of the social networks that were launched for this campaign have served as valuable tools to help with the dissemination of information about the latest contamination. However, such programs as buying foods that are produced closer to home may have more impact.

*  Patricia Walling

Patricia Walling is a web content designer for several healthcare-related sites. She self-identifies as a perpetual student of medicine, and can be found most of the time researching anything
related to the field. She lives in Washington, and as a result loves the long winters.

 

Ten Biggest Food Recalls in US History - link

I was recently contacted by a reader who included a link to a commercial website.  I would not normally publish such a comment, but this site does contain useful information, primarily for American businesses.

The page she specifically included lists ten very large food recalls in the US.  I'm not sure if they are listed in order of cost, volume of product or effect on consumers, and there is only minimal detail.  However, I have included the link here so that interested readers may search further to obtain more detail on these recalls.

http://www.businessinsurance.org/10-biggest-food-recalls-in-u-s-history/

Cidre with that extra fizz could be a nasty surprise

The UK Standards Agency announced on the 18th September that InBev was recalling three batch codes of Stella Artois Cidre in bottles.  Fruit juices and alcoholic beverages make few appearances in lists of hazardous foods and drinks, and this is the first time they feature in Safe Food.

The problem with these batches is yeast.  Yeast is used in bread making, beer fermentation and, of course, Vegemite, the breakfast spread many New Zealanders were brought up on.  So why is yeast dangerous?

Yeasts convert sugar to alcohol and carbon dioxide.  They put the fizz in beers and sparkling wines.  If this occurs in a controlled fermentation process, there is no problem.  However, if yeasts get into finished products containing sugar, such as bottled fruit juices or alcoholic beverages with residual sugar (not fermented to "dryness"), they can produce carbon dioxide in the bottle.  The cells can generate pressures up to 10 atmospheres - sufficient to burst the bottle.

The recall notice says:

• handle the bottles carefully, wearing gloves and protective eyewear, to determine if the product is from the affected batch
• on an individual bottle, the batch code is printed on the bottle’s neck
• on a 12-pack the batch code can be located on the long side of the pack, to the right of the barcode

If you do have a product from an affected batch, please call InBev as soon as possible on 0800 0731736 between 8am and 8pm. Do not consume or handle the product further.



I once saw a similar recall notice that effectively invited anyone having the affected product not to touch it, but to call the bomb squad!

This may sound a bit melodramatic, but think about this:
One of my winemaking colleagues wanted to produce sparkling wine from a batch of still wine.  He calculated the amount of carbon dioxide to dissolve in the wine and added this to the bottles as small pellets of carbon dioxide ice.  He put corks in the bottles and wired them on and then stored the bottles in a cupboard.

A few hours later, there was a tremendous bang from the cupboard.  He found only the necks and bases of the bottles; the rest was fragments, many of them embedded in the wooden walls of the cupboard.  We could only assume that the carbon dioxide had been slow to dissolve in the wine and the pressure had built up too fast.  This could have been very nasty had he been holding a bottle at the time.

As they say in the extreme sports programmes, "Don't try this at home".

Big One becomes Big Seven

Escherichia coli O157:H7 has now been joined on the FSIS most unwanted list by the "Big Six" - other strains of E. coli capable of producing Shigatoxin.

As we saw in May and June 2011 in the German outbreak, Shigatoxin-producing E. coli can cause a potentially deadly food borne infection that can leave survivors damaged for life.  The outbreak also resulted in huge economic loss in several European countries as fresh produce was either banned by authorities or shunned by consumers.

As of the 13th September 2011, these seven strains - O157:H7, O26, O11, O103, O121, O45 and O145 - will not be permitted in non-intact raw beef in USA.  If they are found to be present, the meat must either be destroyed or cooked before sale.

It has been a long road to get to this point. In October 2009, Bill Marler, a US attorney, filed a petition with USDA/FSIS for an Interpretive Rule declaring all enterohaemorrhagic Shigatoxin-producing serotypes of E. coli, including non-O157 serotypes, to be Adulterants within the meaning of the Federal Meat Inspection Act.

Not much has been heard since, though there has been a certain amount of correspondence.  Even the regulatory authorities didn't seem to have a united view.  On the 3rd June 2011, the Deputy Director of CFSAN, Donald Kraemer, stated on the FDA website "FDA considers any disease-causing strain of E. coli in food to be illegal”.  The FSIS deems only O157:H7 to be an adulterant.  Tellingly, Kraemer’s comment was removed from FDA website on 5th July 2011.

The new declaration is being hailed as a victory.  Elisabeth Hagen, head of food safety at the Department of Agriculture, said that this was "one of the biggest steps forward in the protection of the beef supply in some time.  We’re doing this to prevent illness and to save lives.”  A worthy cause.

However, I have some concerns about this optimism.  Will the reclassification of the Big Six make meat safer?  I'm not so sure.  Certainly, if these bacteria are detected in meat, the product will not be allowed on the market unless it is diverted to cooked products.  This may be a challenge for the meat processors - since 1994, O157:H7 in raw ground beef has been declared an adulterant with zero tolerance by FSIS.  In October 2007, the Topps Meat Company recalled 21.7 million pounds of ground beef, bringing the total recalls in the US between April and October 2007 to over 30 million pounds of red meat, mostly hamburger.  A company manufacturing frozen hamburger patties is unlikely to have the capacity to redirect this much meat to a cooking process and there may be difficulties in finding a buyer for the product, so it may have to be destroyed.

Secondly, as far as I am aware, there is no requirement for processors to test for these bacteria.  If this situation doesn't change, the first indication that something is wrong may still be when people start showing up at the hospital with gastrointestinal disease.

Thirdly, the cost of testing is currently very high and the testing may take up to 5 days, even when things go well.  I have already written about the impossibility of guaranteeing safe food by testing.

Finally, testing for the Big Seven will miss any Shigatoxin-producing non-members, as was the case with the German outbreak of O104:H4

The FSIS move is a good start and is motivated by good reasons.  However, the only way that safety of food can be improved is by development of risk management plans and rigorous application of critical control points throughout the food chain, including food service outlets, i.e. farm to fork.  Consumers should not receive contaminated food, but they too must play their part by prevention of cross contamination in the home and proper cooking of foods.  Future posts will deal with some of these approaches.

Where does that leave us with foods like sprouts?  Food for thought.

Since I wrote this article, Shawn Stevens has written an article "Big six declared Adulterants: Is it a good thing?" in Meatingplace.com, a blog for the meat industry in the US.  It seems that he too has some concerns. You may have to register to read the article, but registration is free.