INFLUENCE OF TEMPERATURE AND RELATIVE HUMIDITY ON POSTHARVEST VISUAL QUALITY OF ORIENTAL BUNCHING ONIONS

Li Wu, Beijing Vegetable Research Centre
PO Box 2443, Beijing, P.R. China

Temperature and relative humidity were found to be the two most important environmental factors limiting the storage-life of oriental bunching onions. Weight loss, leaf discolouration and growing point extension were monitored over a range of storage temperatures. Deterioration was more serious at 15°C and 5°C than at 0°C. A temperature of about -2°C is satisfactory for long term storage (5 months). After this time, marketing at approximately 2°C delivers satisfactory quality for about 7 days. Stems maintained better visual appearance at RH 95-100% than at 70-80%, or 40-50%. Growing point extension was controlled by storage in controlled atmospheres. Traditional storage methods do not inhibit colour change and sprouting.

This work was supported in part by ACIAR project 9416.

FOOD SAFETY FOR THE VEGETABLE INDUSTRY

Julia Behrsing & Robert Premier
Agriculture Victoria, Knoxfield (03) 9210 9222

Food safety is becoming an important feature of food production at all levels. This is happening for four main reasons.

• Many major supermarket chains now expect vegetable production to be covered by quality assurance (QA) systems which impose strict conditions on the produce they receive.
• New national ANZFA (Australia New Zealand Food Authority) hygiene standards.
• Increased food safety awareness by consumers.
• Overseas food poisoning outbreaks caused by contaminated fresh horticultural produce.

Food safety issues for the horticultural industry include chemical, physical and microbiological contamination. There has been an awareness of chemical residues and physical contaminants such as presence of insects and soil, for a number of years. However, microbial contamination is now the main concern. The potential safety hazards that are being studied in this new project include microbial, chemical, heavy metal and physical contaminants. The first component of this project considered microbial contaminants.

Potential sources of microbial contamination in the fresh vegetable chain include: soil preparation, planting, fertilisers, irrigation water, harvesting, packing shed, washing, pre-cooling, packing/sorting, transport, distribution, storage, retail.

Microbial contaminants from these different sources include:

• Soil: bacteria eg. Listeria monocytogenous.
• Faecal matter & water: bacteria such as Salmonella spp., E. coli and parasites including Cryptosporidium parvum, Cyclospora. Viruses have also been known to contaminate vegetables and cause illness from these sources.
• Handling: bacteria eg. Shigella spp., and viruses such as Hepatitis A..

Some guidelines already exist and these will be examined for use in our new recommendations. Examples are microbial criteria for water including irrigation, reclaimed and potable water.

The major project outcome will be the establishment of criteria for the clean, safe production of vegetables, with practical and achievable limits. This project will give the vegetable industry an opportunity to set appropriate acceptable limits based on scientific investigations specific for horticulture.

The project is funded by Agriculture Victoria, HRDC and the vegetable industry, and a finalised report is expected to be available by 2001.

ASIAN VEGETABLE INDUSTRY CONTRIBUTES TO CHEMICAL MINOR USE ISSUES

Peter Taylor, TS Agricultural Consultants Pty Ltd (03) 9326 2328

Today's markets for vegetables and other horticultural produce are extremely sensitive to issues relating to pesticides, in particular to pesticide residues and misuse. It is essential that the consumer is protected and is seen to be protected by adequate safeguards in regulations governing the use of agrochemicals. On the other hand, farmers also need to be able to produce clean, marketable crops, which will give reasonable returns on their investments.

Unfortunately, farmers are continually faced with decisions on whether to lose part or all of a crop, or apply a crop protection product that is not registered for the use. The reason for this is that in many vegetable crops, the potential revenue from sales of a given pesticide on the crop is much less than the high costs of registering the product. Agrochemical companies therefore cannot afford to extend product label registrations for these crops. The problem is particularly severe for growers of Asian vegetables.

The Asian vegetable market is in its infancy, but is increasing in size rapidly. The diversity of Asian vegetables available is also increasing rapidly. The small size of the crops and their newness means that almost all of these crops have very few crop protection products registered for use on them. While some of these vegetables fall within certain crop groupings such as "leafy vegetables", "brassicas", "crucifers" etc, there is uncertainty about whether specific Asian vegetable crops can be placed within such groups.

The increased market emphasis on farm quality assurance and documentation of crop protection treatments, together with an increasing need for alternative products with different modes of action (to cope with the emergence of pesticide resistance) greatly exacerbate the problem. It is also an obstacle to implementation of IPM, again because of the prohibitive cost of registering new, "softer" products.

During the past year there have been several instances where residues of agrochemicals have been detected in produce for which the pesticide has no MRL. Recently, the National Registration Authority (NRA), state government departments and industry groups have become more active in helping growers obtain minor use permits for agrochemicals. Now, Crop Protection Approvals Ltd and its subsidiary CPA Research Pty Ltd, will take a major national role.

The principal role of Crop Protection Approvals Ltd. is to co-ordinate applications for permits for minor uses of pesticides to coordinate collection of data to support applications for minor use permits (through CPA Research Pty Ltd.), and to advise primary producers on the use of crop protection products that are the subject of permits.

Crop Protection Approvals Ltd. will negotiate and work with the NRA and the Department of Agriculture Forestry and Fisheries Australia to improve the regulatory system, so that future permit application/granting procedures are more efficient and less costly. An important component of this work will be the implementation of a system of crop groupings for establishment of group MRLs, and the application of the system to minor use approvals.

CPA Research Pty Ltd. will communicate the results back to growers and other stakeholders and will maintain records of permit applications, permits, and of conditions of use on behalf of its client industries.The company has appointed Mr. Peter Dalsanto as Executive Officer for its operations subsidiary CPA Research Pty Ltd.

Contact details for Crop Protection Approvals are as follows:
Suite 5, Moonee Ponds Business Centre
5 Everage St, Moonee Ponds, Vic 3039
Telephone: (03) 8371 0001
Facsimile: (03) 9375 7552
Email: cpa@cpaltd.com.au