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Pickling and processing of gherkins

Boyd Salmon

Parle Foods. Griffith, NSW

Company Background And Development

Parle Foods is a Griffith-based company involved in farming, pickling, processing and marketing of gherkins and gherkin products. It originated as a farming venture growing cucumbers for sale unprocessed. Cucumbers had been targeted as a potentially profitable crop through careful research by Anthony Parle, the now Managing Director of Parle Foods.

After years of successfully growing and selling cucumbers, the decision was made to move into pickling as a means of adding value to the produce. The move into pickling in turn led to processing and further value adding. These pickling and processing developments were seen as an important step away from purely primary production in a primary production area.

It is important to realise that the bulk pickling and processing side of the business has been established only in the past 12 months. This has included the establishment of:

1. state of the art pickling facililties;

2. processing factory with well equipped laboratory, staffed by a Food Technologist and a Biotechnologist;

3. substantial market share in the pickle and relish markets as well as exports.

Parle Foods places significant emphasis on total quality management. This is, in part, a direct result of the way companies which formerly supplied our customers lost their contract through an inability to address quality problems.

We view the role of research as essential in the process of improving product quality and therefore the company's success.

We are currently allocating 3% of total sales towards in-house and external research.

Currently the company produces and sells:

1. fresh cucumbers

2. whole pickled gherkins

3. gherkin-based relishes which end up on McDonald's hamburgers

4. gherkin slices for McDonald's hamburgers


Traditional pickling methods, whilst successful, have proven to be inefficient in terms of quality and waste component when used on a large scale. As a result, new technology was needed to make the venture both profitable and able to meet the quality criteria of our customers.

Post Harvest Handling

It is very important to minimise the time taken to transport, sort and put cucumbers under brine because enzymatic breakdown of fruit proceeds rapidly until fruit is under brine. This is the first step in ensuring a quality product.

The fermentation system is a complicated area considering the time the overall fermentation takes and the fact that the tanks have little protection against the outside environment. The pickling process is a lactic acid fermentation whereby the natural cucumber sugars are converted to lactic acid over a 12 week period by certain lactic acid bacteria. The need to monitor the fermentation process and its susceptibility to contamination and spoilage make it similar to other fermentations, such as wine, beer and cheese-making.

Some of the problems that have arisen in the fermentation process and their solutions are:

1. the build-up of CO2 inside the pickles, known as bloating. This was solved by sparging air through the tanks to remove CO2;

2. enzymatic breakdown of pickle interiors brought about by mould growth. The solution to this problem lay in importing technology from overseas on how to inhibit growth of moulds without impairing growth of lactic acid bacteria and certain desirable yeasts;

3. the suitability of a particular fermentation system to the skin thickness of a particular variety of cucumber. To solve this we used our own trials to select a suitable variety of cucumber to maximise our fermentation system.

The fermentation system we chose pickles cucumbers in bulk in an open yet relatively controlled environment. It is controlled in that the composition of the brine does not change except as a result of fermentation. Although there is no temperature control in the tanks, the tanks' volumes are large and so do not fluctuate greatly, especially in the warm weather of late summer/early autumn by which time the harvest is complete.

When fermentation is complete the pickles will have a lactic acid level of approximately 1% and there should be virtually no residual sugars. In this state the gherkins can be held in the tanks for long periods with virtually no deterioration in fruit quality.


Once fermented, the gherkins are transported from the farm to the processing factory in their brine solution. They are unloaded into a pit at the factory and held here until needed for processing. Whilst in the pit the levels of lactic acid and salt in the pickle are adjusted to meet customer requirements. This is done by adding salt or water to the brine and letting the levels of salt and acid in the brine and pickle equalise. Reduction in the level of lactic acid is especially important due to an unpleasant flavour note associated with lactic acid.

Making Sliced Gherkins

When ready for processing the gherkins are lifted out of the pit by a conveyor into a rod washer which removes any extraneous matter as well as cleaning the gherkins.

This is followed by an inspection to remove defective fruit before entering the slicer. The defective fruit include any broken, bloated, enzyme softened or discoloured gherkins. Once sliced, a secondary inspection is carried out as the sliced gherkins move across a conveyor. Here any slices with holes, incomplete skins or cuts are removed.

The slices then move across a shaker table which allows slices not meeting size specifications to drop through a screen.

A vibratory two-speed automatic pail filler then packs the slices and covers the slices in the pail with a solution including a proprietary blend of spice emulsion.

The pails have use by dates and manufacturing dates written on them as well as the hour of day they were produced, which means product problems are able to be tracked down to one hour.

Making Relish

Cucumbers graded as inferior quality or under- or over-size immediately after harvest are separated and fermented as relish grade. Reject material from the slice line is also used.

The relish grade gherkins are taken through the rod washer, inspected and then fed through the dicer. As a consequence of dicing, the cell walls are ruptured and therefore the diced cucumber is drained to remove excess fluid.

The relish ingredients are mixed together in large mixers, giving good dispersion of ingredients.

We currently manufacture two types of relish. The first, a sweet relish, ends up in the Big Mac sauce for McDonald's, while the second, a dill relish, is an ingredient in the tartar sauce for McDonald's fish burgers.

Tests are carried out on all processed products including slices to ensure customer specifications are met. These include tests on salt, acid, pH as well as gherkin integrity. In addition, no product is allowed to leave the premises without passing microbiological tests for:

(i) total plate count

(ii) yeast and mould

(iii) lactobacillus

The results of all tests are forwarded to customers.

The Role Of Research In Parle Foods

Before entering the fermentation and processing stages, the company had already grown to appreciate the benefits of research in improving the company's performance. Cucumber growing was improved dramatically by trials conducted on the company farm by an agronomist into areas such as:

(i) cucumber variety selection

(ii) irrigation methods

(iii) fertiliser and pesticide use

In addition, mechanical harvesters were developed by the Parle family, with much experimentation. These harvesters have proven extremely successful and eliminate the need for large teams of pickers.

With the lessons learnt through research in the farming side, we are well aware of the potential improvements in the pickling, processing and packaging areas through research. This not only applies to products currently produced by the company; many potential products we have in mind have opportunities for improvement through research. We view research as an integral part of improving productivity and quality.

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