CITRUS PACKING TECHNOLOGY
After a new regulation on the control of citrus canker (Xanthomonas citri subsp. citri) came into force in Brazil in 2017, the post-harvest sanitization of citrus fruit became mandatory to prevent dissemination of the causal pathogen and enable the commercial trade of citrus to other states and countries. Although several sanitizers are available worldwide for decontamination of fresh produce, only sodium hypochlorite is legally required by the country for decontamination of citrus fruit traded with other states and countries against X. citri in the packing house. Thus, the objectives of this study were to assess the efficiency of chlorine dioxide, peracetic acid, and calcium oxychloride as alternative sanitizers and exposure times of 1 and 2 min for the post-harvest decontamination of citrus fruit against X. citri. Sodium hypochlorite, the legally required standard, was used as control. The sanitizers were evaluated regarding the capacity to eliminate live X. citri in solution immediately or 1 h after exposure to the products and the efficiency in disinfesting artificially and naturally contaminated lime fruit. An additional assessment was carried out to determine the infective potential of X. citri suspensions at different concentrations in order to evaluate the risk of disease dissemination by the remaining bacterial population on the fruit following treatment. All the assessed sanitizers were able to completely eliminate X. citri in suspension immediately after treatment. In artificially and naturally contaminated fruit, the sanitizers promoted a significant reduction of 2.4–2.8 and 1.1 to 1.5 log10 cfu/mL, respectively, in the population of live bacteria when compared to the untreated control. In these experiments, the amount of X. citri that remained on the fruit ranged from 0.5 to 1.0 and 0.1 to 0.3 log10 cfu/mL, respectively, regardless of the exposure time. The labeled concentrations and treatment periods assessed effectively decontaminated fruit with X. citri and demonstrated little or no risk of pathogen spread from treated fruit.
The quality of fresh fruit is of vital importance, not only to the retailers and customers, but also to distributors, packing houses and producers. A system to help that the produce reaches the market place in the best possible condition has been developed, aiming specifically at citrus fruit. The developed systems incorporates and integrates sensors, databases and expert knowledge to help with every aspect of the citrus fruit life cycle.
The quality of fresh fruit is of vital importance, not only to the retailers and customers, but also to distributors, packing houses and producers. A system to help that the produce reaches the market place in the best possible condition has been developed, aiming specifically at
citrus fruit. The developed systems incorporates and integrates sensors, databases and expert knowledge to help with every aspect of the citrus fruit life cycle. Keywords: Quality control, Sensors, Data acquisition, Database systems, Monitored control
systems.
The cold chain is vital in the reduction of physiological developments in citrus fruit to prolong the shelf-life and influence market rates. It is also important for some niche export markets that have specified time-temperature cold treatment protocols as phytosanitary risk mitigation measures for pests that they deem to be of phytosanitary concern. The review covers 44 publications that relate to the non-conformance of in-transit citrus shipments with cold-chain specifications. The findings indicate that the literature can be categorised into different themes, namely technological trends, temperature control, and cold-chain modelling and refrigeration. In addition, the key findings from the literature reviewed show that most non-conformances that occur are due to temperature deviations in the cold chain. In addition, the study suggests a framework for successful engagement with the cold-treatment process. The framework adapted from a citrus industry assessment conducted in 2016 provides a detailed explanation of the different phases and processes that need to be followed to help minimise the occurrence of non-conformances, while also detailing some of the disadvantages of the three components that the framework is comprised of. The three components are: the pre-cooling phase, the container-packing phase and the pulp/probe-stabilisation phase. The results of the study serve as a basis to further develop the research area by presenting recommendations and proposing future research.
CITRUS PACK-HOUSE OPERATIONS
Packinghouse operations can be as simple as moving produce from a field lug into a shipping container, or may include a variety of handling practices, from cleaning, waxing, sizing, and quality grading to color sorting. The provision of shade during the packing operations is extremely important. Shade can be created using palm leaf fronds, a plastic mesh or canvas sheet hung from temporary poles, or via a permanent roofed structure. When deciding upon where to locate a packinghouse, access to the field and market point, adequate space for vehicles to enter and leave the packinghouse and ease of access to labor will all be considerations (Proctor, 1985).
In the simplest packinghouse, produce is delivered in picking containers, immediately after harvest, directly to the packers. The packers then sort, grade, size and pack the produce directly into appropriate transport containers. In this case, each worker must be knowledgeable regarding produce defects, grade and size requirements, and packing methods.
As the size and complexity of the packinghouse increases, more operations and workers trained in specific tasks might be added.
Dumping
Produce must somehow be removed from the field bin or harvesting container and moved through the packinghouse. This first step is known as ''dumping". Dumping must be done gently, whether using water assisted methods or dry dumping. Wet dumping can decrease bruising and abrasions by using moving, chlorinated (100-150 ppm) water to carry delicate produce. When using dry dumping, padded, sloped ramps or moving conveyor belts can decrease injuries to produce.
Pre-sorting
Pre-sorting produce is usually done to eliminate injured, decayed, or otherwise defective produce (culls) before cooling or additional handling. Pre-sorting will save energy in that culls will not be handled. Removing decaying produce items will limit the spread of infection to other units, especially if postharvest pesticides are not being used.
Cleaning
For some commodities, such as kiwifruits and avocadoes, dry brushing may be sufficient to clean the produce. Other commodities, however, such as bananas and carrots, require washing. The choice of brushing and/or washing will depend upon both the type of commodity and the type of contamination.
Wash before cooling and packing : tomatoes, cucumbers, leafy greens
Wash to remove latex, reduce staining: mangoes, bananas
Wash after storage : sweetpotatoes, potatoes, carrots
Dry brush after curing or storage: onions, garlic, kiwifruit
Do Not Wash : green beans, melons, cabbage, okra, peas, peppers, summer squash
Sanitation is essential, both to control the spread of disease from one item to another, and to limit spore buildup in wash water or in the packinghouse air. Chlorine treatments (100 to 150 ppm Cl) can be used in wash water to help control pathogen buildup during packing operations ( Moline , 1984). There is some variation in the strength of bleach available commercially in different countries, but a rule of thumb is to use 1 to 2 mls of chlorine bleach per liter (1 to 2 ounces of chlorine bleach per 8 gallons of clean water). Walls, floors and packing equipment can also be cleaned using quaternary ammonium compounds labeled as safe for food processing equipment (Kupferman, 1990).
Waxing
Waxing of immature fruit vegetables such as cucumbers and summer squash; mature fruit vegetables such as eggplant, peppers and tomatoes; and fruits such as apples and peaches is common. Food grade waxes are used to replace some of the natural waxes removed in washing and cleaning operations, and can help reduce water loss during handling and marketing. If produce is waxed, the wax coating must be allowed to dry thoroughly before further handling.
Sizing
Sizing produce is optional but may be worthwhile if certain size grades receive a higher price than others. In most low-input packinghouses, manual sizing is still commonly practiced. Operators should be trained in selecting the size desired and to either directly pack the items into containers or place the selected produce gently into a bin for packing further down the line. Sizing can be done subjectively (visually) with the use of standard size gauges. Examples of the smallest and largest acceptable sizes for each product can be placed within view of the operator for easy reference. Hand held sizers are used for a variety of products.
Many products have established U.S. grades and standards that can assist packers in sorting and sizing produce. The following are examples of standards based upon diameter and/or length.
Examples of USDA Grade Standards: