WA CITRUS maturity testing

As part of the industry development project, fruit is randomly selected from wholesale market floors and retail outlets throughout the season. It’s internal quality is then measured against WA and Australian Citrus Quality standards for juice content and BrimA levels to ensure it has the citrus zing loved by consumers.

Words Bronwyn Walsh, Industry Development Manager, WA Citrus

OUR industry goal is to achieve a 95% pass rates across WA-grown mandarins and oranges for the season. A focus on reaching our goal at the beginning of the season, sets the market up for success in the remainder of the season.

2025 Season Overview

In the 2025 season, 319 fruit samples were tested, with WA grown fruit achieving an overall pass rate of 86% for internal maturity standards. Oranges reached an 88% pass rate, while mandarins were slightly lower at 84% (see Figure 1). Unfortunately, these results represent a decline from 2024, with reduced juice levels being the main reason fruit did not pass in 2025.

The juice content of fruit can be influenced on the farm by several factors, including fertilizer imbalance, water or weather stress, fruit hanging on the tree for too long, as well as soil type and variety/rootstock combinations. Juice levels also begin to drop once fruit is harvested. To help maintain juice content, it may be worthwhile to talk with your supply chain or retailers to ensure fruit is moved quickly to market or retail rather than stored for long periods. If your climate, soil, or rootstock combination tends to produce lower juice fruit, keep a close watch on juice levels and carry out preharvest testing to confirm the fruit has reached the desired juice content before picking.

More frequent or larger sample sizes for pre harvest testing can take into account the variability of fruit across the tree, particularly when testing the first fruit of the season.

All these measures can help ensure our fruit reaches consumers this season at peak quality.

FIGURE 1. Pass rates for postfarmgate fruit during 2025

Mandarins

In the WA mandarin category, insufficient juice levels contributed to 5–19% of fruit not meeting the required standard.

FIGURE 2. The proportion of juice in Clementine and Imperial mandarins samples at wholesale and retail during 2025.

In testing, early season mandarins represented 63% of the fails in the mandarin category. Clementines with a 75% pass rate was the lowest for mandarins, but was up from 62% in 2024. Failed Clementine samples had juice ranges below the 35% standard, from 16% to 34.5% (see Figure 2). The overall average may have been affected by an early sample taken at the end of April. Following Clementines, Imperial performance dropped slightly to 84% of samples passing maturity standards. Failures had juice levels around 5% below the standard. Fruit failed at both retail and wholesale sampling points.

The late season mandarin variety Afourer-type had a similar pass rate to 2024, of 96% for 2025, compared to 85% in 2023. They were the only variety to fail on BrimA in late July at 101, and again at 93 in early September, both below the standard of 110. Gold Nuggets also recorded a few juice related failures.

Mandarin varieties Satsuma, Amour, Daisy, Delite, Hickson, Nectar, Yosemite Gold and Mystique all achieved a perfect 100% pass rate in 2025.

For 2026, consider factoring in your mandarin crop’s position in the alternate bearing cycle, as this affects crop load, likely harvest timing and internal maturity. Additional testing can provide a more accurate understanding of fruit maturity, particularly at the start of the season. Also consider that extended storage, either in the supply chain or on the tree, may reduce internal quality if conditions are not favourable.

Oranges

Generally WA oranges had good BrimA levels in 2025 with only 2 failures by about 7 points. From June to November 2025, low juice levels were a recurring problem in navel oranges, including red flesh, particularly in retail samples. The level below the standard ranged by 2–15% over 10 occasions, with a higher difference in fruit mostly from late June to end July.

Goals for 2026

Individual reports on testing results were sent to each business in March and can be reviewed to assess timing and inform planning for 2026. In 2026, growers are encouraged to take advantage of the free preharvest testing program, especially for Clementine and Imperial mandarins. When collecting preharvest samples, ensure they are taken from across the area to be picked and represent the fruit that will go to market.

Fruit that doesn’t meet maturity standards has a broad impact across the industry. Once distributed to various retailers, it can negatively affect many customers. A single poor taste experience can discourage a consumer from buying that fruit again for up to six weeks, whether it was your fruit or another WA grower’s.

By sending only fruit that meets maturity testing standards to market, we can be confident that WA-grown citrus is the freshest and tastiest available, encouraging consumers to continue choosing WA-grown fruit.