PACK house hygiene and sanitation are fundamental to the supply of safe, fresh quality citrus.
Good pack house hygiene is not only a good agricultural practice, but it is essential to reduce the risk of post-harvest decay, the development of resistance to postharvest fungicides and improve food safety.
Improving postharvest decay control
The control of postharvest decay requires an integrated approach of postharvest handling, hygiene and sanitation, and the correct use of fungicides. The control of postharvest decay with sanitisers and fungicides was discussed in ‘Postharvest decay control — fungicides and sanitisers’ (Australian Citrus News, Spring 2017, pages 12–13). This section summarises some of the key activities to improve pack house sanitation.
Good fruit hygiene starts in the orchard. It is important to train fruit pickers to harvest sound, clean fruit. Care is required for correct harvest and handling of the fruit, as many rots rely on damage (wounds) to the skin for entry and infection. Picking bins also need to be free from contamination and regularly cleaned.
A critical tool to reduce the risk of decay and the level of mould spores in the pack house is to prevent the entry of rotten fruit into the pack house and the removal of decayed and culled fruit from the pack house and cool rooms as soon as possible. Removal of culled fruit and any other accumulated fruit waste should be regularly conducted and disposed of well away from packing facilities. The reduction in spore load within the shed minimises the risk of infection and development of fungicide resistance. It is particularly important to remove culled fruit which roll from the line to under equipment and bins. If undetected this fruit can continuously contaminate the pack house over time.
It is also important to thoroughly clean and sanitise all components of the packing line and equipment, from receival areas to the coolroom. Pay attention to cleaning de-greening rooms and coolrooms where fruit is held for extended periods and where rotten fruit can lead to a higher spore population. It is also ideal to keep packed fruit separate from unsorted bins and away from other potential contamination sources.
While decay control is essential, the absolute fundamental of growing and packing all food, including citrus, is food safety. This is non-negotiable. Food safety is the top priority for consumers in both domestic and international markets. Foodborne pathogens such as Salmonella and Listeria monocytogenes are serious and potentially fatal pathogens that have been linked to horticultural produce.
These pathogens can enter into a pack house with the fruit, in dust storms, on workers, harvest bins, machinery and other objects (living and non-living). It is critical to have a food safety plan to minimise these risks. The most important protection against any food safety problem relies on the pack house workers. It is critical that all workers are aware of food safety risks and properly manage their work to minimise any risk.
To support workers to maintain food safety standards:
Educate and train workers about the personal hygiene and food safety risks linked to fruit handling and processing.
Provide eating, drinking, smoking and toilet facilities away from the processing area.
Hand wash stations must have a cold and hot water supply along with a soap, disposable paper towels and a bin.
Managing food safety risks in the pack house is a key component of any food safety plan. Some important considerations for the pack house hygiene include having a pack house access and layout that:
Restricts access to visitors.
Prevents entry of dust, dirt, birds, insects, rodents and animals including pets.
Segregates handling areas for unprocessed and processed fruit.
Pre-treatment or washing of fruit with water containing a sanitiser is essential to minimise the risk of bacterial pathogens and reduce fungal spores.
Citrus fruit are generally not considered a carrier of foodborne pathogens (e.g. Salmonella) due to their high acidity and inedible rind. But recent research has shown that bacterial pathogens present on the citrus rind may get transferred to hands and mouth of consumers during peeling and eating. Therefore, the use of a sanitiser is important to mitigate food safety risks and to complement the fungicide treatment through its action on moulds and yeast.
A number of sanitisers with different chemistries, including fungicides, are currently available in the market and are registered with the Australian Pesticides and Veterinary Medicines Authority (APVMA). Each sanitiser has its own merits and demerits of adoption. The selection of sanitiser is influenced by a number of factors such as price, water source (channel, ground or council) and quality (pH, hardness), method of application and monitoring (manual vs. automatic), packing line machinery (corrosiveness) and buyer’s requirement etc. These are discussed in ‘Postharvest decay control — fungicides and sanitisers’ (Australian Citrus News, Spring 2017, pages 12–13). However, it is important not to solely rely on sanitisers to control any postharvest food safety issues. An integrated approach is required to develop a food safety plan.
Key points to include in a cleaning and sanitising schedule:
Develop and implement a food safety plan with written procedures for cleaning and sanitising food contact and non-contact surfaces.
Food contact surfaces (harvest bins, packing line) must be cleaned and sanitised using food grade detergents and sanitisers.
Non-food contact surfaces (floors, walls, ceiling and drains) must be cleaned and sanitised regularly.
Cleaning and sanitation of packing line equipment is critical. Just one source of pathogen introduction, at any point, can potentially inoculate all fruit that pass through the line.
Therefore effective cleaning is critical to maintain food safety of the pack house and minimise postharvest decay. The University of Florida publication ‘Fresh Produce Handling, Sanitation, and Safety Measures: Citrus’ (2002) summarised the key cleaning tips for citrus packing lines as follows:
Cleaning — physically removing debris, biofilm build-up, and any other residuals on the line. This is done with detergent and physical labour (such as scrubbing or a pressure washer, etc.).
Sanitation — using sanitisers of various types to kill microbes on clean surfaces. Sanitation is most effective after a surface has been cleaned. This is true of packing lines, hands, bins and anything else that may become soiled.
Many steps can easily be overlooked during cleaning. Here are some key points to remember:
Remove debris accumulation from all surfaces.
Clean all surfaces that fruit or workers may contact, including bench/table tops, drains, walls, cooler coils, ceilings, etc., as appropriate.
Clean using a top-to-bottom method to avoid re-soiling already cleaned surfaces.
Closed-in spaces can be fumigated for sanitation.
Never put fruit that has fallen from the line back into circulation.
Have waste receptacles available for worker use and regularly empty and clean them.
Properly store all equipment after the work day ends.
Regular cleaning greatly reduces opportunities for pathogen build-up and inoculation to occur.