News Limiting risk

Limiting risk

MRLS, EHIS, AND THE BENEFITS TO INDUSTRY & CONSUMER

In 2022, pest management decisions are a huge consideration for growers, who must prepare, plan, pre-empt issues and protect the reputation of industry. The Australian Table Grape Association (ATGA) project lead Alison MacGregor talks about export harvest intervals – what they are, and how they help grape producers satisfy quality standards in export markets – and a new ATGA project designed to help growers make pest management decisions easier.

In a post-Covid world, consumers are seeking healthier snacking options with high levels of antioxidants to help repel viruses. Consumers also enjoy the back-story about food they eat – they want to know its provenance, and that it is “clean and safe” – grown using environmentally friendly growing practices.

For grape producers, that means careful planning and record keeping with regard to chemical use.

Planning includes knowing how long to wait (days) after applying the last spray, before harvesting fruit, to allow residual chemical to degrade to the levels accepted in each export market (called a maximum residue limit, MRL).

Sometimes export MRLs are lower than Australian MRLs. In that case, the length of time required to meet the export MRL is likely to be longer than the withholding period on the chemical label. The time period required to meet an export MRL is called an export harvest interval (EHI).

The ATGA will partner with Cherries Australia and Summerfruit Australia Limited in a project funded by Agriculture Victoria to gather residue data and apply a model that calculates the decay of chemicals, for estimating EHIs for grape exports.

ATGA will model EHIs for eight chemicals initially, giving priority to late-season botryticides, and insecticides. Some data will come from the chemical industry and some from the Food and Agricultural Organisation (FAO) of the United Nations/World Health Organisation (WHO).

EHI recommendations for grape markets will appear in the ATGA MRL app. But only if suitable data is available for the model (i.e. the data must meet international standards used by the FAO for setting internationally agreed (Codex) MRLs).

The industry must avoid a “rubbish in, rubbish out” situation. EHIs

won’t be reliable if poor data are used in the model. If an unreliable recommendation leads to residues being detected in an export market, Australia's table grape industry gets a bad reputation.

It will take time to gradually populate the ATGA app with reliable EHIs. Currently the app defaults to a very long EHI if an export MRL is lower than the Australian MRL.

There are several reasons that another country might set a lower MRL in grapes compared the Australian MRL. For example, if Japan has already established MRLs for Chemical X on stable foods (rice, soy, leafy greens and a range of local fruit), then their total diet might already contain close to the acceptable daily intake (ADI) for Chemical X. As a consequence, when Japan reviews MRLs for additional food types, including grapes, they can’t permit any more of the chemical into their diet and must set very low MRLs for those other foods. v

Alison MacGregor amacgregor@atga.net.au

A label's "withholding period" (WHP) refers to the time interval to meet the Australian MRL

Opposite page: Project lead Alison MacGregor advised growers to think of the end user of their product – the consumer. Top: Sunraysia laboratory ALTSA is a NATA accredited facility which conducts residue testing of a number of chemicals used on table grapes. Picture: ALTSA

The export harvest interval (EHI) refers to the time interval to meet export MRLs.

Successful exporters don’t take risks regarding export MRLs.

Somewhere in the chain, the grower or their agronomist or agent are probably following these steps:

1. Prepare a list of chemical options for your spray program.

2. For each chemical on your list, compare the Australian MRL with the MRLs of your target markets.

3. If any export MRLs are lower than the Australian MRL, plan to use a longer EHI than the label withholding period, and keep good records for the auditor and agent.

4. Send samples to a NATA approved laboratory for residue testing, just prior to harvest, and request a test that is relevant to grapes.

5. Check the residue test results before committing grapes to any market, because if residues exceed an MRL in that country then the fruit must be diverted to a different market. Testing before shipping reduces the risk of a shipment being rejected on arrival because residues were found.

The ATGA extension team is available to help industry members to locate laboratories with NATA accreditation for relevant chemicals.

The maximum residue limit (MRL) is the maximum concentration of a residue, resulting from use of an agricultural chemical, which is legally permitted to be present in or on a food, agricultural commodity, or animal feed.