Watch the wash for food safety in fruit production

Page last updated: Thursday, 16 November 2017 - 3:36pm

Please note: This content may be out of date and is currently under review.

Water is a basic requirement for all organisms, including microbial pathogens. In fruit growing and where water is an input, there is also the potential for harmful bacteria to thrive.

All quality assurance (QA) schemes list water as an input to be managed for potential hazards. The challenge with managing water quality is its variability due to multiple environmental factors which are beyond grower control.

However, growers can control water quality at point of use in fruit packing operations. The importance of this was clearly demonstrated in the tropical fruit industry in separate incidents in recent years.

On two occasions, Western Australian tropical fruit was contaminated with Salmonella and traceback linked the source to the wash water. A treated water source was in use and no previously known issues had been identified with the fruit from routine laboratory testing.

After extensive investigations the source of one Salmonella incident was found to be equipment that served to repeatedly inoculate the wash water. Hence, chlorination of the water was insufficient to resolve the contamination and it was only after complete strip down and sanitation of the whole wash system that Salmonella was eliminated. Some components of the wash system also needed to be replaced.

The equipment had been purchased second-hand. For effective food safety control all newly-acquired equipment must be cleaned and sanitised, then appropriate samples taken and sent for testing to verify it is safe to use. Good sanitary control of the wash water is required and can be maintained by keeping free chlorine levels at a minimum of 50ppm.

The second Salmonella incident is also believed to have been caused by contaminated wash water with the original source possibly being wildlife.

Producers are often frustrated by abundant, protected birdlife that carry Salmonella and other pathogens. However, the solution to this problem is in active risk assessment. When birds are more active, ramp up your food safety controls. For example, increase free chlorine levels in the wash tank, reduce the time between water changes in recycle systems and send samples for testing more frequently.

Active risk assessment needed

Assessment of food safety risks on properties and in packhouses is an ongoing process. It is not something to be thought about once a year just before the next audit.

  • Do you know if water quality in your operation is changing?
  • If so, do you know what is causing the change?
  • Do you know how to manage the change to keep food safety under control?

The pathogen levels on pre-packed produce (fresh-picked or out of coolstore) change through the year and need to be monitored through the season in your verification testing program so you can adjust your sanitation program to manage the higher levels. If you don’t, you could be under-controlling the pathogen levels and letting contaminated produce out to customers and consumers.

These are some of the questions to ask on a regular basis. Having the answers to these questions demonstrates an understanding of Hazard Analysis and Critical Control Point (HACCP) that underpins your quality assurance program.

You also need to consider what happens to your product through the supply chain. If not washed prior to cutting, contamination on the fruit skin can be transferred to the flesh. It is wise to have controls in place to ensure any contamination on the fruit skin is not transferred to the flesh when cutting.

These Salmonella incidents cost the producers about $65 000 in direct costs and immeasurable damage to their brand. The potential is for an entire multi-million dollar, multi-State industry to be put at risk.

Small cost increases to manage water in use, sanitation chemicals and risk management analysis to retain control of your food safety program is a good piece of insurance for your business and a small price to pay in the long run.