Imagine something small enough to fit on your hand that could raze your business with the flick of a switch.
For The Burger Bar in Albury, that’s exactly what happened back in January, 2010. It destroyed the business, and the impact it had on the owners was also devastating. In the process it also gave over 100 people food poisoning.
Last week I had the opportunity to share a beverage or two with Lauriston Muirhead, an environmental health officer from Albury City Council. He was one of the first guys in after the Salmonella Bomb had gone off, and had the grizzly job of finding it. Listening to his first hand account helped clarify many of the urban myths that have popped up around this case, as well as really making me rethink raw egg products such as aioli – yet again.
What is a “Salmonella Bomb”?
According to Lauriston, research about 1 in 20,000 eggs sold are slightly damaged and allow bacteria on the outside to enter the egg, and by bacteria we mean salmonella. Once salmonella is inside the egg it has the perfect environment to multiply. Keep in mind that this was also in the middle of summer and so not only did the salmonella have nutrients, it also had the perfect temperature as eggs are not required to be refrigerated.
So a raw egg filled with salmonella is “Salmonella Bomb”. Eat a raw bomb and you are guaranteed to have the worst bout of food poisoning imaginable. They are so potent that they can be diluted down to give hundreds of people food poisoning, and that’s exactly what happened at The Burger Bar.
Why don’t we hear about “Salmonella Bombs” more often?
Salmonella Bombs are like hand grenades – they are safe unless you pull the pin. For eggs, if you cook them you will kill most of the bacteria. Since most people cook their eggs, the risk is significantly reduced. Note that “gooey” eggs aren’t thoroughly cooked.
The other thing to keep in mind is that most eggs are consumed by a single person. So if a “Salmonella Bomb” goes off, it will only take a single person out with it. That makes them more of a “Salmonella Bullet”.
What makes a really good “Salmonella Bomb”?
To make a really effective Salmonella Bomb, it needs to be used raw, and it needs to be in something that is mixed up with other ingredients to make a large quantity. This then allows it to be shared with many people.
For The Burger Bar they made their own special aioli with raw eggs. This was a burger joint that was ahead of the times. Now every second burger joint has their own special aioli. This means that a “Salmonella Bomb” could go off anywhere.
The fog that could have hidden the truth
When an outbreak of salmonella occurs, the inspectors will use a number of techniques to identify the most likely cause. In many cases the food has already been consumed or disposed of and the “proof” is no longer available. Proof in this case is a good swab or sample that the lab guys can get excited by.
In the absence of “proof”, or as a faster way of getting to the truth, interviews are critical. Asking customers, staff and the owners questions is essential to helping identify potential causes and ruling out causes. It helps identify if it was a particular dish or ingredient, or if it was general.
In this case, the aioli was used in most burgers and so wasn’t immediately identified. The fog that hid the truth was being told that none of the staff ate the burgers. This was because it was the restaurant’s policy that staff were not allowed to eat while at work, and the owners assumed this was the case. Since staff were also sick, and staff “did not eat the food”, the initial suspicions indicated a viral infection such as Norovirus rather than bacterial food poisoning.
Fortune, interviews and science revealed the truth
It was lucky that there was still product left to sample. Careful interviews by NSW Health and luck revealed, fairly early on, that, in at least one instance, where people had the same product, the customer who asked not to have aioli because they did not like it, were not ill while their dining companions were. This was nearly as good a “proof” of the cause of the problem as the laboratory tests of the samples which came through several days later confirming very high levels of Salmonella in the aioli.
There were three fairly distinct groups of customers who ate product from the same batch- most were fine, some were really sick and some were mildly sick.
This did not appear very logical at first sight.
The best guess is that the Salmonella Bomb went into the second of three mixes for that batch. Anyone who had it felt the full force of the Salmonella Bomb. Anyone who had the first mix was fine. The customers who had the third mix, however, were exposed to the cross contamination.
Who was at fault?
We like to be quick to identify blame. In the original story I heard, the restaurant had been guilty of leaving the aioli out in the heat of summer and refrigerating overnight. That makes for a really great story, especially since I sell temperature loggers and it is a story about the evils of room temperature. If you do have anything with raw eggs in it, the message is still very clear – it must be stored below 5°C. That’s a no brainer.
But according to Lauriston, the aioli was kept at the correct temperature. As soon as a batch was made, it was labelled with date of manufacture and refrigerated. When Lauriston sampled it from the service salad bar it was actually frozen at the bottom of the container. At this stage I will point out that this conversation was being had over a beverage in a bar. There were no lawyers present and while the truth is important, what I really wanted were practical lessons.
This also happened 7 years ago. It was as a result of this incident and many similar incidents that the Food Authority cracked down (pun intended) on damaged eggs. It should be noted it is very hard to detect a fine crack in an egg in a busy kitchen. The point I wanted to make was that the restaurant was doing things “by the book”.
What has changed since 2010?
The biggest change is the requirement for raw egg products to use a method to control bacteria. Such products must be acidified to a maximum pH of 4.2 or have some other effective processing step to make all raw egg products safe.
The NSW Food Authority has some great information on what to do if you are using raw eggs. They have great tips like…
How do you minimise the risk of Salmonella Bombs?
The first tip is – don’t crack a raw egg! If you do want “raw eggs” there are pasteurised alternatives that can now be used. Save the real thing for cooking.
The second is to ensure that they come from an authorised supplier. This ensures that they are properly cleaned and inspected. They aren’t perfect and Salmonella Bombs still exist, but they are far less likely.
There are now pH requirements for raw egg products. This makes the environment more hostile to bacteria. It won’t necessarily fix a Salmonella Bomb but it will muffle it.
If you are eating at a restaurant, how do you avoid Salmonella Bombs?
You can’t judge a restaurant just by its appearance. Salmonella Bombs have gone off in top class restaurants as well as cheap dives.
If I’m having anything with aioli, I ask if it is freshly made or bought. Bought aioli (or mayo) is probably fine. It won’t be the same dining experience as some boutique home made aioli, but it should be safe to eat.
I used to then ask when it was made. If it wasn’t fresh, then it’s not worth the risk. That’s because I thought the problem was time and temperature related. It’s still a good question, but it doesn’t protect me against a Salmonella Bomb.
So what is the one question that will protect me against a Salmonella Bomb?
You can’t taste it to see (boom). You can’t smell it because it will smell fine. You can’t see it. You can’t ask if there is a Salmonella Bomb in it.
But there is one question that you can ask, and this question may well save your life (or at least save you two weeks of extreme misery).
Ask the waiter this one simple question…
“what is the pH of your aioli?”
Do not expect them to know the answer. They are the waiter. They will need to ask the chef. If they aren’t prepared to ask, or if the chef doesn’t know, then you have a choice – either leave or find the most processed item on the menu – because they either don’t care or know about food safety.
A good chef, however, will be able to tell you the pH of the aioli because they know and care about food safety.
Of course they could just pull a random number out of the air, or give you the official answer. They may even choose to spit in your aioli for being a know-it-all. Chances are, however, this one question will quickly sort the professionals from the wanna-bes.
How do you avoid a Salmonella Bomb at home?
Now that’s a tougher question.
If you are into any of those drinks with raw eggs, home made aioli, or just like downing raw eggs (move over Rocky) then there are some simple tips:
- never use cracked eggs,
- never use cracked eggs,
- never use cracked eggs,
- never use dirty eggs (cook them, though in theory you can’t buy dirty eggs anymore),
- consume what you make and toss the leftovers
- make small quantities
- wash your equipment and bowls between batches
And just realise that you have a 1 in 20,000 chance of swallowing a Salmonella Bomb.