Sunday, March 27, 2011

Poor Understanding - Raw Milk in New Zealand

Last week, I read an interesting article by Jill Galloway in the Manawatu Standard entitled "Selling milk as it was meant to be".  The story was about the increasing sales of unpasteurised and non-homogenised milk at the farm gate.  Unfortunately, the author and/or her interviewees made a number of errors.

Under New Zealand law, sales of raw milk from the farm gate have been permitted for several decades.  All other milk and milk products must be pasteurised or given an approved alternative treatment. Section 11A of the Food Act 1981 allows for producers to sell up to five litres of raw milk at any one time from their farm gates to people who intend to consume it themselves, or to provide it to their families.  However, the milk must be harvested under an approved Risk Management Programme under the Animal Products Act 1999.

So if farmers follow the rules, there should be no problem about safety.

However the article went on to express some strange views.

For example: "People believe in the integrity of food.  People want to know where it comes from. Processing destroys dairy products".

Or how about: (Farmers) "are up against rules, regulations and science".

But my favourite was:  "Before processed milk, there was no heart disease. Homogenisation means the fat particles are small enough to be ingested, not digested, and go straight through to the blood and arteries," Ms M. says. She thinks homogenisation began because people thought the fat on the top of milk was bad and they did not want to see it.

Hang on a minute.  If Ms M. is correct, then the dairy companies are actually delivering what consumers are demanding.

Second place goes to Farmer C: "When it is pasteurised, the milk becomes dead. People don't want to be eating or drinking dead stuff."

So you never had a steak, Mr. C?

I guess I should not poke fun at these people, who genuinely believe that their product is better than pasteurised milk.  And indeed, they are producing their product according to the NZFSA regulations.  But it does worry me that people can be so smart in some aspects of their lives but authoritatively make such ignorant statements.

Wednesday, March 23, 2011

A bridge too far for Bio-enterprise?

If you look back over the posts of the last three years, you will see that the vast majority are about microbiological food safety issues.  There are other safety concerns, not all of them justified.

If you were going to fly from Seattle to Los Angeles, would you go via Hong Kong?  Not unless you were forced.

I have just returned from the NZBio 2011 conference, where the theme was "Enabling Successful Bio-enterprise".  The conference was attended by delegates from far and near - businessmen, entrepreneurs, venture capitalists, regulators and scientists.  Over three days, I heard papers on drug development, bio-fuels, bio-marker molecules and bio-plastics.  I didn't hear a single paper on food.

This surprised me.  When I began my career, I helped to develop the ICI Single Cell Protein process.  This was a high-tech attempt to solve a perceived looming food shortage.  The development was a technical success, but an economic failure.  The cost of feedstock rose dramatically and, even back then, the costs of testing and getting approval for human or even animal feeding were prohibitive.  The protein was high quality, but there were difficulties of acceptance and the public probably thought that it was too reminiscent of sci-fi foods.  The SCP concept was, perhaps, an approach to food supply ahead of its time.
Now, through beautifully sophisticated molecular biology techniques, we have the opportunity to produce more food, with desirable characteristics such as longer shelf life, slower or faster maturation, better nutrition and better functionality.

Why are bio-enterprises not taking advantage of these procedures to increase our food supply and are instead choosing to manufacture medical test kits, bio-fuels and making the very risky investment in new drugs?

I think the answer lies partly in the massive misinformation campaign against genetic manipulation and safety of Genetically Modified Organisms (GMO).  There; I named the elephant in the room.  The public has been so mislead about genetic manipulation that bio-enterprises consider that it is just too financially risky to invest in GM products.

I questioned a panel of experts about this.  The consensus of those prepared to comment was that foods derived from GMOs will be accepted and on the market in 10 to 20 years.  Currently, research and development organisations are going to great lengths to get to a product they could achieve much more quickly and easily by genetic manipulation.  This is like forcing a mechanic to fix your car with stone tools or doing the SEA - HKG - LAX trip.

Currently, there is no real shortage of food, just a maldistribution.  But the growing world population and increasing lifestyle expectations will eventually lead to food shortages.  GMO-derived foods may help to alleviate these shortages and add to the arsenal of functional foods and nutraceuticals.  This will not happen until the safety of GMO-derived foods is demonstrated, the public begins to trust scientists again and the misinformation campaigns are shown for what they really are.

I don't claim to be an expert on GMOs.  If you want to follow up on the safety of GMO-derived foods, have a look at:

Assessment of the food safety issues related to genetically modified foods. Harry A. Kuiper, Gijs A. Kleter, Hub P. J. M. Noteborn and Esther J. Kok (2001) The Plant Journal  27(6), 503-528

Wednesday, March 16, 2011

Black Humour

I have been a consultant to the food industry for the last 33 years and in that time, I've seen some things that would be funny if they were not so disturbing.

A few years ago, I was helping a food factory to gain control over the level of contamination in their products.  The company manufactured a very large number of product lines, some of which were essentially assemblies of cooked foods with fresh salad vegetables.  The levels of microbial contamination in finished goods were obviously not under control and sometimes spiked well above the Microbiological Reference Criteria for Foods

The company was doing regular wash down of the entire production facility, though their finished goods still showed irregular spikes of contamination.  I began doing regular checks of hygiene in the factory.  I asked them to change the way that the cleaning was conducted, so that there was no food exposed during the cleaning and that the equipment was cleaned top-down.  The product contamination continued.

On several occasions, I pointed out that they were cleaning the food contact surfaces well, but that the fabric of the factory was not being cleaned so well, particularly the floors.  Some of the mutterings went along the lines of "We don't process food on the floor".  Yes, of course, but wet floors allow growth of bacteria in food residues and generation of aerosols, which can settle onto food contact surfaces and in-process food.

The last straw came when I pulled up a floor drain and showed the manager the thick gray biofilm on the fitting.  This can't form overnight or during a shift - it had not been cleaned for at least a week.  The manager responded with "That's not our biofilm".  Being an erudite conversationalist, I said "Huh?".  "No", he replied, "the drains back up and that's how the biofilm gets there, but it's not ours".

Hands up all those who are surprised that this manager successfully managed the company into receivership.  Nobody?  Thought so.

Saturday, March 12, 2011

Toxic seaweed was a red herring

The tragic death of beautiful Kiwi backpacker, Sarah Carter, in Thailand last month was initially blamed on a meal containing toxic seaweed.  Sarah and two other women suffered vomiting and heart complications while they were staying in Chiang Mai.  Privately, I thought that this explanation was highly unlikely, partly because of the symptoms and partly because it appeared that only these three were poisoned.

It now seems that Sarah had been infected with an ECHO virus.  These Enteric Cytopathic Human Orphan viruses are found in the gastrointestinal tract and primarily cause disease in children.  (Their name originated in the 1950s, when cell culturing allowed the viruses to be identified, but no disease was associated with them). 

ECHO viruses are highly contagious and exposure to them can result in an infection of the lower intestine, which then spreads to other organs.  Death is usually the result of overwhelming liver failure or myocarditis (inflamation of the heart muscle).

Because of their association with the gastrointestinal tract, ECHO viruses are usually transmitted by unhygienic conditions and person-to-person transmission via the faecal-oral route.  Respiration of infected droplets and contact with fomites (contaminated objects) may also be important in transmission.  I believe that it is significant that three other people died of heart problems in the same hotel in the space of two weeks, though a doctor from the Thailand Department of Disease Control said that the elderly British couple who died both had blocked arteries.

I guess that the messages we can take from this tragedy is that foreign travel is wonderfully mind-broadening, but that visiting areas where environmental and food hygiene are poor can be hazardous to health.  We should be careful, however, before thinking that Asia is the only
place we can contract ECHO viruses - poor hygiene can be found in any country.

Sunday, March 6, 2011

You can lead a horse to water, but you can't make her drink

Another saying from my childhood, translated from the original Yorkshire dialect into English!

What triggered this?  Well, HACCP (Hazard Analysis and Critical Control Points) has been around since 1959, when NASA attempted to ensure that food fed to astronauts would not make them ill, or cause injury.  The possibility of early astronauts, trapped in orbit and vomiting into their helmets, could not be contemplated.  Originally developed as a microbiological safety programme by the US Natick laboratory and later by The Pillsbury Company, the Modes of Failure programme eventually covered all aspects of astronaut food, not just microbiological hazards.  By 1971, the HACCP system was published and documented in the USA and by 1985, the National Academy of Science recommended the use of the system. Incidentally, I began teaching HACCP to food technology undergraduates in New Zealand in 1978.

Recently, Roy Costa posted an article on Food Safety and Environmental Health Blog:
in which he pointed out that retailers demand food safety management systems from suppliers.  The end of the supply chain - institutions and food service organisations - are also required to have HACCP-based food safety plans in place, but schools seem to have dropped beneath the regulatory radar: few have implemented the requirements and they are not being pursued by the local health departments.  Costa suggests that this is because the schools and health departments are both part of the counties, which claim that this is an unfunded Federal Government mandate. 

Politics aside, this problem of lack of implementation of HACCP-based food safety plans is not restricted to schools and food service outlets.

Some years ago, I wrote an HACCP-based food safety programme for a local food manufacturer.  This is not something I will do again; as a consultant, I was an outsider and though I had a close familiarity with the factory, I don't think that the production manager wanted to do more than "tick the box" that they had a programme.

About a year after I wrote the programme, one of my students got a job at the factory.  "What do you think of the HACCP programme?" I asked.  "What programme?" he replied, "I never saw it".  The next time I visited the factory, I mentioned this to the manager.  He said "Oh, I'm sure it's around somewhere, probably on the shelf in my office".

So, after that roundabout story, we come back to the title of this posting.  The factory complied with the regulations - it had an HACCP-based food safety programme, so any auditor could be shown the document.  But just having a nicely bound document on the shelf is only the beginning.  The plan must actually be implemented in the factory and reviewed on a regular basis.  This manager wasn't even sure where it was, his staff didn't know of its existence and there is no doubt in my mind that he never reviewed it.

Thursday, March 3, 2011

More on Listeria contamination of vegetables

On 18th January 2011, I wrote about the withdrawal of salad vegetables from certain supermarkets in New Zealand because of possible contamination by Listeria  (See Listeria Hysteria).

 This week, I came across a paper published in Food Microbiology, describing the transfer of Listeria innocua from contaminated compost and irrigation water to lettuce leaves.  (M. Oliveira et al. Food Microbiology 28 (2011) 590-596).

These authors noted in their introduction that "Fresh produce can become contaminated at any point during the primary production, processing, distribution and preparation.  Primary sources of preharvest contamination include soil amended with untreated or improperly composted manure, contaminated irrigation water, the presence of wild and domestic animals, infected workers, and unclean containers and tools used in harvesting.  Research has demonstrated that many human pathogens are able to survive for extended periods in soils, manure and water."

Listeria monocytogenes causes Listeriosis, a rare but serious disease in humans, with an incidence of 2-3 cases per million of the total population in England and Wales.

In their experiments, Oliveira et al used an avirulent strain - Listeria innocua.  They transplanted lettuce seedlings into pots containing soil and contaminated compost;  compost manually surface irrigated with contaminated water after the seedlings were transplanted; and treated a third set of seedlings by hand-spraying contaminated irrigation water onto the lettuce leaves after transplanting.

These workers reported that the lettuce leaves became contaminated with Listeria from the soil and, not surprisingly, sprinkling with contaminated water also resulted in contamination of the leaves with Listeria, which survived for some daysThe bacteria survived in the compost for more than 9 weeks, giving ample opportunity for contamination of the leaves by transfer of soil.

Clearly, as these workers showed, irrigation water used for fresh salad vegetable growth must be pathogen free and manure used in compost must also be treated to remove pathogens.