Lies, damned lies, and misinterpretation of the data.

I am constantly amazed by the apparent ignorance and credulity of the general public on matters of food safety and nutrition.  But should I be surprised?   Few people are lucky enough to have studied food technology, food science or nutrition.  Their main sources of information are then the popular press, magazines, television cooking shows and the all-pervasive Internet. 

Scientists and engineers know that the best sources of information are peer-reviewed papers published in international journals.  Experts in the field have read the paper and picked it apart, looking for poor experimental design, inconsistencies and faulty interpretation of data.  Believe me, I can say this with certainty from both sides of the fence: it is pretty difficult to get a paper published these days!

The other sources of information mentioned above are generally not peer-reviewed.  Articles can be published by people with no formal qualifications in the subject and are often either highly biased or downright wrong.  See:  http://foodsafetywithjaybee.blogspot.co.nz/2015/04/dangers-of-google-degree.html

Sensationalism and sycophantic following of media celebrities are what sell newspapers and magazines.  We see more food scares and wonder diet advice every month without any reference to the original research.

A few examples spring to mind:

Towards the end of October 2015, the WHO International Agency for Research on Cancer stated that processed meats, including hot dogs and sausages would be added to its list of high risk carcinogens.  Red meats were also declared a probable carcinogen.  Needless to say, this caused a furore in all the media.  A Google search, using the terms “sausages cause cancer” returned 469,000 results!  IARC classifications rank the quality of the evidence that something can cause cancer, but don’t assess the level of risk. The announcement was often quoted out of context.  For example, Discovery News baldly stated “Eating sausages, ham and other processed meats causes colon cancer”.  Other reports mentioned the increase in risk as a percentage, but did not state the base level of risk. This scare is enduring; at a barbecue recently, someone noted that I was cooking “cancer sticks”.

Coconut water appears to have been a major drink commodity this year. I have no sales figures, but the sales in 2013 were around half a billion dollars, see http://www.stuff.co.nz/life-style/well-good/75567921/how-healthy-is-coconut-water.html.  Claims for coconut water include helping with weight loss, improving skin tone and aiding digestion.   Other claims, now withdrawn, stated that it could fight kidney disease, osteoporosis and viruses.  Coconut water contains potassium, calcium, magnesium and phosphorus, which are required minerals.  As a sports rehydration drink, coconut water is definitely unsuitable - when we sweat, we lose lots of sodium.  The ratio of sodium to potassium in sweat is about 10:1, but the ratio of sodium to potassium in coconut water is around 1:3.  Where are the peer reviewed scientific studies of the value of coconut water? They are never quoted.

Critics of the hypothesis that saturated fat consumption is linked with coronary heart disease use the argument that the correlation between total saturated fatty acids and risk factors is not very good.  Unfortunately, the scientific findings have been misinterpretated by the popular press media, with the result that we are told we can eat as much saturated fat as we wish. This advice is incorrect, unethical and irresponsible, see http://nzifst.blogspot.co.nz/2015/10/the-recent-non-scientific-comments.html.

Despite all the information on food safety available, in my opinion, a large proportion of the population is still badly educated in this regard.  At an outdoor party this week (it's summer in New Zealand) I sat with a very-soon-to-be mother.  She got stuck into the soft cheese in a big way, but said that she would eat it only during the first half hour of its being unwrapped; thereafter it was to be avoided.  In fact, the cheese had been made with pasteurised milk and she was therefore probably safe in eating it, but where had she got this idea from?  I guess she had read about Listeria in soft cheeses, and believed that the bacteria could multiply as the cheese warmed up.  For reliable information on safe foods to eat during pregnancy, see:  http://www.foodsmart.govt.nz/information-for/pregnant-women/list-of-safe-food.htm

I believe that food scientists and food technologists have a duty to provide unbiased and easily digested (sorry!) information to the public in order to help educate them in food safety.  But how can we compete with big advertising budgets and the pronouncements of media celebrities?

I wish all my readers a happy, successful and safe 2016.

Comment on potential hazards of raw milk consumption.

I was recently asked for comment on the tragic death of a youngster in Australia, apparently caused by consumption of raw milk.  I was given only 200 words to get the message across.  Rather than go over all of the arguments again, I have reproduced my comments below:

The recent tragic death of a 3-year old infant and serious illness of four other children in Australia is  yet another example of the risks associated with consumption of raw milk.

Proponents of the consumption of raw milk claim that this is a natural food and has been consumed for hundreds if not thousands of years.  That is true, but ignores the fact that many diseases can be transmitted from animals to humans in the milk.

The hazards of consuming raw milk have been known for a long time. In Ontario around 1900, over 10% of all childhood tuberculosis was thought to be caused by unpasteurised milk. The rate of tuberculosis infection and many other milk-borne diseases in children fell dramatically after enactment of a law in 1938 requiring milk to be pasteurised; this was hailed as a major achievement.

The fact is that between 1998 and 2005, a total of 45 outbreaks resulting in more than 1,000 illnesses, 104 hospitalisations and two deaths due to raw milk or soft raw milk cheese were reported to the US Centres for Disease Control and Prevention. 

There is some evidence that consumption of raw milk early in life can reduce the incidence of allergies.  Bacteria in the raw milk may transiently colonise the intestine, resulting in stimulation of the immune system through infection.  

In addition, when milk is digested, a variety of beneficial ‘bioactive peptides’ are released.  However, it should be noted that pasteurisation does not adversely affect the release of these peptides.

I have said this before and say it again:  Adults who decide for whatever reason to consume raw milk should consider the potential hazards and make an informed decision.  Children, who have no choice in the matter, should not be fed raw milk or soft raw milk cheeses.

The situation is a little different for hard cheeses, such as Parmesan, in which the conditions, or the process, are inhibitory to most pathogens.  Food Standards Australia and New Zealand has made the following determinations:

• Extra hard raw milk cheeses pose a low to negligible risk to public health and safety as survival and growth of Campylobactyer jejuni/coli, enterohaemorrhagic Escherichia coli (EHEC), Salmonella spp., Staphylococcus aureus and Listeria monocytogenes is very unlikely.

• The selected Swiss-type raw milk cheeses were all assessed as posing a low to negligible risk to public health and safety for the general population as survival and growth of C. jejuni/coli, E. coli (EHEC), Salmonella spp. and S. aureus is very unlikely. 

Note:  The FSANZ document is comprehensive and readers should consult the report for more detail. See:  http://www.foodstandards.govt.nz/code/proposals/documents/P1007%20PPPS%20for%20raw%20milk%201AR%20SD3%20Cheese%20Risk%20Assessment.pdf

•

Mould, the consumer and the retailer

Many searchers of this blog have asked "Will spoiled food make you sick?"  I have commented on this before.

Over the last few weeks, I have purchased two blocks of cheddar cheese from a large supermarket chain in New Zealand.  When they were opened, both blocks were found to have a few mould colonies growing along the edges and at the corners.  This became apparent when the plastic film was peeled back.

Do these mould colonies represent a health hazard?  According to Dr. John Pitt, Aspergillus flavus is unable to produce aflatoxin at refrigerator conditions, so it is unlikely that there is a health hazard if the cheese is eaten.  I just cut the mould off, together with a bit extra to avoid eating cheese with changed flavour resulting from the mould growth. 

My wife, who is obsessed with "food going out of it's date stamp" suggested that the cheese might be old,  ("Well, that's why you buy mature cheese, dear"), but the best-before date stamp was mid-2013.

I wrote, complaining to the supermarket chain and pointing out that there were probably only two reasons  that these blocks of cheese could have had mould growth inside the pack - the cheese was packed under poor hygiene conditions in which mould spores were able to contaminate the block, and maybe the film had been pulled too tightly at the edges and corners, increasing the gas permeability and allowing air to penetrate the pack to allow the strictly aerobic moulds to grow.

No harm, no foul you might say.  But the consumer is entitled to buy safe, wholesome food and to have mouldy cheese only when mould is part of the normally accepted description of the cheese, such as Brie, Camembert and Roquefort.  Cheddar is not mould-ripened.

What I found interesting about this, besides the technical issue, was that the supermarket chain completely ignored my complaint, not even sending some sort of "We are looking into it" brush-off.  Do they not care about consumer perceptions of their stores, or does this happen so often that they feel it is 'normal'?

Tuberculosis and Mexican cheese

Quite by chance, on the day I was writing my last blog article on raw milk, the Orange County Register published an article by Doug Irving on an outbreak of tuberculosis in San Diego. See http://www.ocregister.com/ocregister/homepage/abox/
article_2060722.php?orderby=TimeStampDescending&showRecommended
Only=0&oncommentsPage=2#slComments

Mycobacterium bovis is relatively rare in humans, but can be serious and difficult to treat. It is thought that the disease jumped from cattle to humans somewhere between 8000 and 4000BC, when cattle were domesticated. There is archaeological evidence that humans suffered the disease, pulmonary tuberculosis, which may have been contracted through consumption of raw milk. The human specialized form M. tuberculosis was probably spread by migrating Indo-Europeans and by 1000BC it had spread to the whole of the known world.

It appears that in the San Diego area, the disease is spreading primarily through the Latino population and scientists there believe that it may be being brought into the country from Mexico in queso fresco, a popular soft crumbly cheese that may be produced as a cottage industry.

The article in the OC Register contains some inaccuracies. Not all milk sold in the USA must be pasteurized; it depends on the particular State legislation. In addition, the article implies that the outbreak has suddenly flared. However, the actual study by UCSD Medical Center and county health officials, showed that between 1994 and 2005, there were 3,291 cases of active infection reported by the county's Tuberculosis Control Program and of those, about 8 percent were ill with M. bovis. Roughly the same pattern was observed in 2007.

The sale of raw milk cheeses in New Zealand is currently limited and subject to strict controls. See http://foodsafetywithjaybee.blogspot.com/2007/06/
free-choice-or-safety-of-population.html
Extra hard Italian Parmesan-style raw milk cheeses like Grana Padano, Pamigiano Reggiano, Romano, Asiago and Montasio have a low water activity of about 0.693, which prevents the growth of bacterial pathogens.