Problems with Salmonella are not common in Australia as most commercial farms follow strict food safety procedures.
We are always amazed at the things we see people getting away with at markets - even Farmers' Markets which claim to only have accredited stallholders .
Here's a brief run-down about Salmonella and how good operators can easily avoid the problem.
Salmonella is a bacteria that can be found on many farms. Chickens carry the bacteria in their bodies, and pass Salmonella into the yolk and white while eggs are being formed in the ovaries. Bacteria may be deposited on the eggshell when the egg is laid and then in the right conditions, the bacteria can pass through the shell pores into the egg itself.
Despite a common belief, cracked eggs are not generally responsible for Salmonella problems. An intact shell does not guarantee safe eggs. The key is good on-farm hygiene practices with rodent control, clean nest boxes, clean grading and packing facilities and adequate cool storage. Eggs should be clean when they are laid and regular collection and good handling practices prevent the spread of bacteria.
Any part of the egg can harbour bacteria, and both whites and yolks have been implicated in food borne illness. However, the yolk is the most common source.
Chickens can be infected with salmonella bacteria from their environment, which is easily contaminated by rodents, birds and flies. These carriers take the bacteria to all types of egg farms whether they're cage, organic or free-range. The totally controlled environment of cage systems probably makes the problem less likely there as long as feed, water storage and egg handling facilities are up to scratch.
Once the bacteria get inside the chickens, the micro organisms thrive under ideal temperature and conditions.
When the eggs have been laid, multiplication happens fast if the eggs aren't cooled quickly. And if there's a lapse in cleaning practices or an undetected outbreak among the chickens, the percentage of affected eggs can increase rapidly.
Salmonella bacteria can double every 20 minutes under ideal conditions. In an hour at room temperature, two bacteria could become 32. At two hours, there may be 1,000 organisms. At eight hours, there can be millions in one egg.
One of the big problems for consumers at markets is that eggs are often transported halfway across the State and are not kept in temperature controlled conditions. The eggs may leave the farm on Thursday or Friday for deliveries in Melbourne and some may not be sold until a Sunday market.
If those eggs are well cooked, they should present no problem – but if they are eaten raw or in an undercooked form, gastroenteritis is often the result.
According to press reports, the problems with the latest contamination issue has been a combination of poor egg handling procedures and the number of eggs laid on the floor of the sheds rather than in nest boxes. The company's answer appears to be to import an egg washing machine to wash all eggs produced on the farm.
This outbreak demonstrates why industry accreditation programs are a fiasco.
Here's the latest from Green Eggs as published: