Salmonella Typhimurium is the most common strain of food poisoning in Australia and is on the rise, mostly being traced back to egg products, so it was a priority to find out more, according to researchers from the University of Adelaide.
The researchers found no instances of Salmonella Typhimurium within internal egg contents, despite looking at known infected chickens in a year-long sampling survey of poultry farms with caged chickens.
Salmonella infection sources include on an egg farm or in backyard hen houses from people who are handling the product, rodents, poultry feed or dust.
Different potential sources of contamination on egg farms and the supply chain to determine what influences the level of Salmonella found is next on the agenda.
Dr Kapil Chousalkar, senior lecturer in the school of animal and veterinary sciences, said the focus is on the external environment and handling because Salmonella can be transmitted on eggs and can penetrate through the shell if not stored properly.
He told FoodQualitynews.com that while the study was on selected egg farms in South Australia, the hope is to expand to look at all Australia and maybe other countries.
“We found birds which were positive with Salmonella but they were not shedding that in the egg.
“Salmonella Typhimurium was on the egg shell, outside of the egg but Mother Nature has designed an egg shell with multiple layers to prevent entry. Inside, the egg white has anti- bacterial properties which is another defence.”
The country has minor exports of eggs to South East Asia but the majority is internal.
He said the focus was on Salmonella Typhimurium instead of another strain, Enteritidis,as the problem in Australia was not on the same scale compared to Europe in meat or egg products.
Researchers at the University's Roseworthy Campus are investigating the journey of salmonella "from farm to fork".
They will examine Salmonella in chickens and contamination of eggs, and the transmission of the bacteria from the environment to the bird and then onto the egg.
Public info need
Dr Chousalkar said the work is a start because of the talk about Salmonella and it being a long term issue in Australia but data in the public domain was limited.
“For solving the problem we need to quantify the problem, the next stage is education on handling practices through the channels in the supply chain and control strategies on farms.
“We must work out what preventative measures are needed, there has been work in broilers, looking at probiotics, vaccines, organic acids.
“But we need to know what is the best time to use organic acid and with vaccination there has been some work done but we need to look at it in more detail.”
The study was done in caged birds but the hope is to expand it to cover free-range and cage free birds, like the system in Europe.
“There are a lot of things to understand, such as where it comes from, educating the handlers and there is no silver bullet to completion. We need to educate people who handle egg and egg products," he added.