Research reveals citrus contamination risk

Research reveals citrus contamination risk

New research shows citrus fruits can carry foodborne pathogens such as Salmonella.

These pathogens can survive the sanitisation process of the packing shed, according to Dr SP Singh, NSW DPI, who shared the preliminary research conducted by NSW DPI at the Food Safety Forum in Barmera, SA, last week.

“Food products are potential carriers of these pathogens and citrus is no different to any other food,” Dr Singh said.

Dr Singh conducted preliminary research, funded by NSW DPI, three months ago to provide scientific evidence and raise industry awareness.

Bacterial pathogens can come from contaminated irrigation water, water used for applying chemicals on trees; dust storms, which can spread pathogens from compost yards or animal manure from nearby farms; native wildlife; and from workers not washing hands after toilet breaks and picking fruit.

“Growers thought that once contaminated fruit goes through the shed it is sanitised. Fruit washing and sanitisation can only minimise the microbial load, it cannot make the fruit sterile.”

It remains on the skin of the fruit but can be transferred to the flesh when peeled or cut with a knife. The pathogens can also be transferred to hands, which can then be put in the person’s mouth.

Citrus was inoculated with Salmonella in a laboratory as part of the experiment.  It was still present after four weeks when stored at room temperature (20 degrees celsius); and could survive for two weeks at 4 degrees.

Dr Singh said other pathogens, like Listeria monocytogenes can survive longer in all conditions including cold storage. Although the fruit may not support the growth of these pathogens but they can potentially survive through the supply chain.

Dr Singh told the audience that food safety was critical for an industry like citrus which is heavily dependent on exports.

“Considering citrus industry’s footprint in the export markets, food safety is the number one priority. We propose and support Citrus industry’s microbial risk mitigation plan underpinned by a solid science and driven by a food safety culture being nurtured by the industry”

He made mention of the recent foodborne illness outbreaks in fresh produce in Australia and overseas, which cost the industry millions of dollars and lost consumer confidence.

“Rebuilding consumer confidence and export markets is the most difficult task. If there’s any market failure, vendors will lose market access, and that would be a disaster.”

The NSW DPI will propose an industry funded project to investigate potential hot spots for contamination and cross-contamination across the entire supply chain. Dr Singh said he received support from growers at the Forum for further research, and a microbial risk mediation action plan for industry.