Making Strawberry Jam

Processing FoodThe fruit preserves you buy in supermarkets are the product of many dedicated people whose efforts are coordinated into a complex team effort. The process or recipe for making preserves is fairly simple and has been done in home kitchens for many years. Through more than 30 years of experience in the application of food science and processing engineering, Processors/marketers, such as Safeway, have been able to develop large-scale processing methods to improve quality and consistency found in the home kitchen.

The starting point is the farmer's field. The coastal valleys of California, Oregon and Washington produce the finest fruit in the world. Safeway buys the best of this crop from the premier growers of the region. Fruit is hand picked in the fields and quickly transported to packing houses where it is cleaned and quick frozen to maintain color, flavor, texture and to prevent spoilage. Properly frozen fruit, when held under the right conditions, will maintain its quality for several years. However, the freeze/thaw cycle does cause some damage to the fruit regardless of how carefully the process is done.

The best preserves are made with fresh fruit (never frozen). The fruit is chilled and shipped directly from the packing house to the preserve plant where it is processed within 24 hours. In addition to buying only from premier growers and packing houses, field inspectors regularly visit the packing houses to ensure that the fruit meets the quality standards.

The frozen fruit is held in cold storage warehouses. These warehouses, which are gigantic freezers, keep the fruit at the proper temperature to insure that it maintains its optimum quality. Just prior to cooking and packaging the fruit is shipped by truck to the preserves plant, inspected by trained food chemists and thawed under careful observation to the proper point.

As stated earlier, the starting point is the field, but the real beginning is when the marketing manager makes the decision as to the number and kinds of preserves to pack. This decision is made from 18 to 20 months in advance and is the result of many hours of research and consultation. This advance forecasting of future demand must be done so that the purchasing agent can make buying commitments during or prior to the harvest.

Within one to two weeks of the actual pack date, the plant's production control manager will make a detailed schedule of which products will be produced on any given day. At that time he and his staff will issue purchase and release orders for the elements needed to produce the finished product such as: jars, caps, labels, glue, etc. It is the production control manager's responsibility to have all the items needed in the plant at the right time.

Once the production schedule has been made, the plant operations people meet and review the schedule in detail. This group includes the departmental foreman, the maintenance manager, the quality control manager, the production control manager, the production manager and supervisors. It is at this meeting that the final details are decided on and all the activities of the various departments are coordinated.

From three to five days prior to production, the fruit is received at the plant, inspected by the quality control food chemist and set out to thaw. The fruit is thawed to the point that it can be managed but is still at the freezing temperature of 32º F. Once the thawing process has begun, the packaging process is committed. The fruit cannot be re-frozen without harm.

The commercial production of preserves uses two to three kinds of sugar, depending on the variety. Different kinds of liquid sugar and dry sugar may be used. The sugars are received in bulk by truck and stored in tanks and silos. In addition to the fruit and sugars, a small amount of pectin is used to provide the set to the liquid portion of the preserve. The original preserve recipes used gelatin, an animal product. However, gelatin has been replaced by pectin, a natural fruit product, from which the term jelly comes. A small amount of citric acid, another natural fruit product, is used to adjust the acidity for flavor consistency.

The evening before the pack begins, plant mechanics are busy preparing the equipment. All the machinery is thoroughly inspected and lubricated. Any worn or otherwise damaged parts are replaced and equipment is adjusted. In coordination with the mechanics, the clean up crew is cleaning the cooking and packaging equipment so that everything will be ready for production.

At 5 a.m., on the day of production, the cooking crew arrives. The first thing they do is inspect the kettles and other equipment to verify that everything is thoroughly cleaned and ready for use. While the inspection is conducted, others in the cooking crew are preparing the fruit and other materials.

The first step is to blend the fruit and other materials in the pre-cook kettles at a relatively low temperature. A single batch will make enough material to produce approximately 1,500 jars of preserves. The proportion of fruit and sugar is regulated by the federal government; therefore, the blending operation as well as all other operations must be carefully controlled to comply with all regulations and maintain high quality standards. The fruit blend is transferred to vacuum pans where excess water is cooked off and the proper balance of sugar between fruit and juice is obtained. (A recent development has been the introduction of all-fruit spreads. These products are similar to preserves, but they are made with concentrated grape juice instead of sugar.)

The water is cooked off in vacuum pans so that the product can be brought to a boil at a low temperature, improving quality. If the product were cooked in open kettles, it would darken and the texture and flavor of the fruit would not be as good. The cooking process is consistently monitored by quality control personnel. The cooking operation, along with the fruit buying and selection, is the most important factor in determining the quality of the finished product.

Once the quality control department has determined that the batch is cooked to perfection, the product is transferred to a holding tank where it is held for a short time. Depending on the ripeness and variety of fruit, the cooking process takes approximately three hours. The filling line is the next process. The product is passed through a heat exchanger and then over inspection tables where any leaves or stems that may have been missed at the packing house are removed.

The preserves must be hot filled and capped to prevent spoilage. This is a moderately fast operation involving 200 jars per minute. Immediately after the filling/capping operation, the jars move into a cooling tunnel and the product is cooled to room temperature. The final step in the packaging process is the labeling and casing operations. The labeling and packing machines are highly complicated and perform delicate gluing and application procedures at very high speeds. Once the jars are in the case, the case is glued, closed and printed to identify the product, date and time.

The finished product is then stored in the plant warehouse to await shipment to regional warehouses around the country. These warehouses then distribute the preserves to the stores. Although the basic process is rather straightforward, it requires a dedicated team of professionals to maintain consistently high quality standards.