Old lessons not learned - Re-post

I have just returned from a meeting of food experts in Wageningen, Holland. One evening, we were taken to the Zoo in Arnhem. This fantastic place has a number of indoor environments, such as a jungle, ocean, desert and a restaurant.

After the visit, we had a meal in the somewhat inappropriately named Burgers Zoo Restaurant. A feature of this is the do-it-yourself barbeque. This ingenious device is like the continuous toasters you see in some hotel dining rooms – the food is placed on a continuous belt grill and passes over heated briquettes. Diners select their meats and salads from the large range set out on side tables.

Not having completely switched out of professional mode, I watched my fellow foodies to see how they would cope. I guess I should not have been surprised to see several of them take their raw meats and salads onto a single plate. They cooked the meats and then put them back onto the same plate! Nobody took fresh tongs or heated the ones used to put the meat on the grill.

Clearly, not all the participants were experts in food safety, but I had hoped that they would know about basic food safety rules – cooked food should NEVER be put on a plate that has held uncooked meat and cross contamination of salads from raw meats must be avoided. When I pointed out their mistake to a couple of my colleagues, they understood, but still didn’t know what to do about it.

At the other end of the scale, one young lady expressed concern as to whether she had cooked her steak sufficiently and was she at risk of food poisoning? In my opinion, her meat was over-cooked, but it would certainly have been safe to eat. Raw steaks from a healthy animal are essentially sterile on the inside, so they can be made safe by cooking the outside properly. (Minced or ground meat has had the outside mixed into the inside, so cannot safely be eaten rare). She expressed the view that barbequing was a bloke’s job, but I wonder if it should be left to food microbiologists?

Safe Food has a following!

I noticed today that someone has become a Follower of Safe Food. Thanks, Kim.

You can keep track of new posts if you click the "Follow" tag next to the search box at the top of Safe Food. Your picture, contact details and other followings will appear in my Blogger Dashboard, but currently will not appear on the page. If you have a Blogger Dashboard, you can set up a reading list and new postings will appear there.

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I hope that these enhancements will help you to benefit from reading Safe Food.

Guest Editorial - Additives in New Zealand Foods

This blog has not been updated for some time, mainly because we have been hard at work studying the growth of Cronobacter sakazakii. This work has now been submitted for publication and I have time to write more articles. Some of our work on C. sakazakii will appear in a later post.

To get us off to a good start, here is a guest article, written by one of my colleagues, Associate Professor Owen Young of Auckland University of Technology:

Food Additives in New Zealand

I recently had AUT University students systematically survey packaged food labels in Auckland supermarkets for health claims. These could be real (e.g. ‘if you eat this food your cholesterol will be lower’), or implied (e.g. ‘contains no additives’, ‘all natural ingredients’ etc.).

Over 30% of products surveyed had a ‘fat’ claim such as ‘lo fat’, ‘low in saturated fat’, or ‘98% fat-free’. Arguably these claims could be useful to a buyer seeking to control their weight, but overlooks the fact that total energy intake is really what matters for obesity. Fat is not the only beast with calories.

But of more interest to me were the claims for avoiding Public Enemy Numbers 1, 2 and 3: artificial colours (28% with claims), preservatives and artificial flavours (both 24%). Anyone would think these things were dangerous. But are they dangerous in the way they are used in foods?

Take the yellow food colouring tartrazine for example. Googling ‘tartrazine allergy’ will score you thousands of hits. On the face of it you would have to wonder why Food Standards Australia New Zealand (FSANZ) allows artificial food colouring to be used at all. The reason is because the evidence for adverse effects from these colours is so flimsy as to be laughable. Colours have been used in foods for decades with no adverse effects. So why are some colours banned in certain countries? The reason is that pressure groups have been so strident that it becomes politically expedient to roll over and appease the activists.

Preservatives are sometimes put in prepared foods to minimise the growth of bacteria. These bacteria can either degrade the food, but be otherwise harmless, or they can be pathogens. At best the latter can make you sick and at worst can kill you. The maximum quantity of preservative added is typically hundreds of times lower that the amounts required to show any kind of response in humans. Preservatives have excellent safety records, and that is why FSANZ allows their use. You would have to wonder about a food manufacturer who neglected to add a preservative to a susceptible food. Such action should be viewed as callous indifference to your health.

The so-called artificial flavour that gets most bad press is MSG, monosodium glutamate. Ostensibly MSG is responsible for the Chinese restaurant syndrome with its claimed headache, flushing, and tingling symptoms. But MSG has been used extensively in Asian cooking for donkey’s years. If it’s so bad, why doesn’t everyone in Asia have a headache? The truth is that it is not bad for you.

Very many common foods have high concentrations of MSG, but no one complains about MSG in cheese, soy sauce, walnuts and broccoli, and a host of other foods. Chinese restaurant syndrome is nothing but an enduring urban myth. So why does MSG have to be declared on labels? One reason is that regulators are simply responding to activist demands. Any hint of a potential problem is dealt with by a label declaration that presumably implies that the additive is a risk and so feeds the myth.

What can or cannot be added to food in New Zealand is governed by FSANZ’s Food Code, which is online for all to read. One guiding principle is you can put additives into foods only where allowed and where needed – up to a specified limit – and crucially, only enough to achieve the required result. You cannot add stuff just for the hell of it, and indeed why would you? Additives cost money and there is often no need for them.

Take beer for example. Current advertisements frequently have an ‘all natural ingredients’ claim ­– whatever ‘natural’ means – and a ‘no preservatives added’ claim. The Food Code allows only one preservative in beer, sulphur dioxide, but it is seldom added because beer, by its very nature, keeps well without preservatives. Similarly, preservatives are not added to breakfast cereals because they are not needed in these dried foods.

The Food Code is thus a very conservative document, making New Zealand food supplies among the safest in the world.

So feel free to ignore the implied health claims that are built on the flimsiest of evidence, and are used to part you and your money through a fear of chemicals – chemophobia (n): an irrational fear of chemicals, particularly those man-made.

Associate Professor Owen Young is Academic Leader, Food Science, AUT University, Auckland

It’s not quite about food safety…

Recently I was asked by a reporter to test magazines found in doctors’ waiting rooms for presence of pathogens. She wanted to do a story about the risks of going to the GP. I wasn’t sure what to expect, but asked her to collect a range of magazines from various waiting rooms. She brought me ten glossy or super glossy magazines covering popular women’s and men’s titles.

Each magazine was opened randomly and two pieces of the right hand page were cut aseptically, using sterile scissors. Each piece was 100mm x 100mm; one piece was cut from the top right, the other from the bottom right. This was to increase the chance of sampling the area most handled by readers.

The pieces of paper were transferred to a sterile bag with sterile diluent and massaged thoroughly by hand and then for two minutes in a machine called a Stomacher. I transferred samples onto agar plates that would enable me to assess general microbial contamination, faecal bacteria and Staphylococcus.

After incubation, I examined the plates, looking for typical bacterial colonies. The levels of contamination on all media were low. The limit of detection in this analysis was 3.7 colony forming units/10 cm². In the food industry, a count of less than about 100 cfu/cm² is considered acceptable, though the count on food contact surfaces at the start of food processing should be close to zero. Thus, the analysis I used was sufficiently sensitive to indicate whether the magazines were microbiologically hazardous with respect to Staphylococcus and faecal bacteria.

Staphylococcus is typically found on the skin and can be transferred to food and there produce enterotoxin, which causes food poisoning when we eat the contaminated food. It is unlikely that the low levels of S. aureus detected in this work would lead to significant transfer between readers. No typical colonies of faecal coliforms were detected, suggesting that there were no, or very low numbers of faecal bacteria on the magazines and hence that the likelihood of faecal contamination of the pages was also low.

All of the samples were printed on glossy paper, which doesn’t absorb water, a fact I confirmed by measuring the water activity* of the samples. There was thus no opportunity for bacteria to grow on the pages and in fact, they may have died off reasonably quickly.

One thing I should point out is that it is not possible by any simple analysis to detect viruses, so the work done here doesn’t completely rule out contamination by viruses of upper respiratory tract or gastrointestinal tract origin. Some, such as the Norwalk virus that causes gastroenteritis, can survive on surfaces for long periods.

I conclude from this cursory examination that, with the possible exception of viruses, the pages of the magazines were relatively free of pathogens. Handling the magazines is therefore relatively hazard free. However, as always, it would be advisable to wash or sanitise hands before consuming foods, snacks or sweets after visiting the surgery.

Have a happy and safe Christmas, everyone. Make sure your Christmas fare and BBQs are safe.

* For a description of water activity see:

http://foodsafetywithjaybee.blogspot.com/2007/06/free-choice-or-safety-of-population.html

Raw milk and people with influence

It’s happened again! Bill Marler quotes a Washington State Department of Agriculture News Release, reporting that three recent Escherichia coli infections in Washington have been linked to drinking raw, unpasteurised milk. The Washington state departments of Health and Agriculture have put out new warnings about the risks of consuming unpasteurised milk and milk products.

All the patients involved have reported drinking raw milk from the same supplier. Though no E. coli have been found in the most recent batch of product tested, the Washington State Department of Agriculture did find in the dairy the same strain involved in one of the illnesses.
Bill Marler, Doug Powell and I have all written on many occasions about the hazards of consuming raw milk. Doug has emphasized that personal freedom is all very fine, but young children cannot exercise freedom of choice. They are often the ones made ill by bacteria carried in raw milk. If you think that we are a bit over the top on this issue, have a look at the You Tube clip of Barb Kowalcyk talking about her son, Kevin, who contracted haemorrhagic E. coli infection.

http://www.marlerblog.com/2009/12/articles/legal-cases/perfectly-healthy-to-dead-in-twelve-days-hemolytic-uremic-syndrome/

A few days ago, Tamati Coffey was shown on TVNZ’s “Breakfast” programme milking a cow and then drinking the milk. No real problem there. The show’s hosts, Pippa Wetzell and Paul Henry then discussed the merits of drinking raw milk. Typically, Paul reckoned he wouldn’t touch the stuff, but I was surprised when Pippa, who recently had a new baby, argued that drinking raw milk is good for you. Many people watch this programme every day and there must be a proportion of those who are mothers of young children. Judging by the daily feedback, viewers hang on every word the presenters utter. I have to admit that I too enjoy the quick repartee of Paul and Pippa, but her throwaway line could easily influence parents to feed raw milk products to their children, with potentially disastrous consequences.

Perhaps television presenters should be a bit more careful when it comes to expressing views on the safety of foods – they are not trained in food safety. As they said in the post-war years when I was a lad “Careless talk costs lives”. It’s just as true today.

New technology to double avocado shelf life: NZL FOODweek Online Main Features Page

New Zealand FOODweek Online published an article on high pressure processing (HPP) of avocado to extend shelf life. The link is shown below:

New technology to double avocado shelf life: NZL FOODweek Online Main Features Page

HPP has been used for some time, particularly in Japan for cold pasteurisation. In a future blog article, I will write about HPP and explain how it works and how it can be applied to foods.

“The Law is an Ass” – with apologies to Mr. Dickens.

In the last week, the Far North District Council in New Zealand has enforced the law and required community members to desist from cooking pickles and jams and selling them through a Hospice Shop. Over the years, these wonderful people have raised around $5000 for the hospice funds each year.

It appears that the District Council received a complaint that the goods were being produced in private kitchens. Under the Food Hygiene Regulations, the council was then obliged to investigate. The regulations specify that production of foods for public consumption may be conducted in unregistered premises only on special occasions.

This situation crops up more than you might expect. About 25 years ago, when my children were small, our country school raised significant amounts of money by pizza drives. About three times a year, the Parents Association purchased commercially made pizza bases and assembled pizzas for sale. The council received a complaint from a commercial pizza parlour that this was unfair competition, since the school did not have a registered premises and therefore had lower costs. We were able to comply with the regulations by specifying the number of times a year our Occasional Food Premises would be used and by registering a relatively simple Food Safety Programme.

To give credit where it is due, the Far North DC and the New Zealand Food Safety Authority (NZFSA) are looking at ways the volunteer cooks can continue to produce their foods. Their home kitchens are not registered premises and it is not practical for the volunteers to set up a separate kitchen. I’m looking forward to seeing how the Authority gets around its own antiquated regulations.

However, what is the real risk? The products are essentially heated, acid foods – jams are made from acidic fruit and have a low water activity*, so the most likely microbial spoilage – if there were to be any – would be mould growth, which would be apparent to the consumer. Pickles are acidified foods and the low pH has the same effect, preventing the growth of pathogens. So the microbiological risk to consumers is low. Fruit cakes and similar baked goods are not hazardous either. Obviously, good hygiene in production and handling of all these foods is essential and potential contamination with cleaning chemicals etc. must be prevented.

What are the most hazardous foods on sale today? According to the Centre for Science in the Public Interest, these are leafy greens, with 363 outbreaks (13,568 reported cases of illness); eggs (11,163), tuna (2341), oysters (3409), potatoes (3659), cheese (2761), ice cream (2594), tomatoes (3292), sprouts (2022) and berries (3397). These are listed in order of outbreaks. Notice that jams, pickles and cakes don’t figure in the statistics.

Back in the Far North, everyone is looking to see this resolved soon, so that the volunteers can resume their work for the hospice. The Food Hygiene Regulations are due for replacement with a new Food Act that will shift the emphasis to risk assessment of food processing operations.

As the Assistant Director of NZFSA apparently said, “The law isn't based on common sense and we're looking to improve things."


* See the end of "Free Choice or Safety of the Population" for an explanation of water activity.