A Plan for Internal Recycling

A Plan for
Internal Recycling
May 1995 - Process Engineering

By: John Spizzirri
Contributing Editor

  The terms waste minimization and recycling have become ensconced in industry jargon, and their implications, while not always looked upon favorably, are inescapable. Industry journals, local newspapers and national magazines abound with articles on every aspect of these issues, from cleaning up the waste stream to edible packaging. Often referred to in environmental terms, the issues are also matters of cost and efficiency.

  Despite efforts to keep lines running smoothly and to make better use of ingredients, food processing always generates a certain amount of waste. This may include anything from the expected scrap dough on a cracker line to an entire batch of vanilla ice cream base containing double the required amount of vanilla flavoring thanks to a scaling error. Whether by design or by accident, dealing with such waste material can be costly.

  Reworking product is an effective way to minimize loss or, better yet, turn it into a profit. Many companies have taken advantage of scrap or damaged items and returned them to their respective bins and hoppers or, in some instances, created branch products. The obvious benefit of using rework is, of course, cost savings. Unless it is reintroduced back into the original product, the unused portion is sold to other markets at a lower price or it finds its way to the landfill. Having it hauled away can be more expensive than storing it for a short time and using it again.

Staking a re-claim

  Not all products and processes lend themselves to the practice of rework, but bakery goods and confection manufacturers provide a good example of its application.

  "I usually tell my students, 'baker's don't throw things away,"' says Ron Zelch, director of cakes and sweet goods at the American Institute of Baking (AIB), Manhattan, KS. "Generally, bakers learn to put it into crumbs, work it into a coating, or mix it back into a dough."

  The product and the efficiency of a line often determine the percentage of scrap likely to be produced, as do the various manufacturing processes. Several industry sources have suggested between 1% and 3% as a realistic range, one that lends itself as a manufacturing control and as a figure for use in the product development phase. The product itself also determines to what extent rework can be used.

  The baking industry reclaims both raw scrap and cooked, damaged goods (often called, "cripples.") Uncooked dough scraps from bread or crackers are channeled back to the mixer and reintroduced at a controlled rate. Darker breads, such as wheat and multi-grains, can handle about 3% rework based on total weight before it begins to affect volume, says Wulf Doerry, director of cereal technology at AIB.

  Cooked scrap consists of product that does not come out according to spec - say, in terms of appearance. It is then considered damaged and dumped into a scrap tank, stored or returned to the production line. While reworking uncooked material is fairly straightforward, there are a number of factors to consider when reintroducing cooked products or ingredients into fresh batches.

  When bakers reuse stale sweet dough products or bread product cripples, they must account for a certain amount of water absorption. Coffee cakes, for example, are either broken up or ground and added in large quantities to sugar, shortening, butter and almond paste for use as a filling. Because the rework contains gelatinized starches, extra liquids are added to produce a spreadable filling.

  Hearth breads, such as French bread, have harder crusts that aren't so easily concealed in fillings. Hydrating the crippled bread with water, however, allows them to be reworked into subsequent dough batches. In this case, a high-shear blender might be used. This type of mixer uses a high-speed agitator and can produce a slurry of one part rework and three parts water. Such a slurry would then be added to the dough at a rate of 12% of the flour weight, or 3% rework and 9% water based on flour weight. But they would have to compensate for the water that's carried with the rework by subtracting it from the other dough water, says Doerry.

Salvaging solutions

  Multi-component products are a little tougher to work with. Again, it depends on the product. For manufacturers of additives for the baking industry, it becomes a question of whether the chemical process lends itself to the practice of rework. Icing stabilizers that fail to meet quality assurance specs can be reanalyzed to discern missing components, or matched with the components of other formulas to which it might be added.

  "In some instances, we can only reprocess about one-third of the product and then there may be some part that has to be hauled off," says a source for one manufacturer. Various dry-blending operations, he says, generate a fine dust that is collected to keep it from dispersing into the air. Because the volume is low, the dust collected in such a system often is combined with that of two or three other products made on the same line. This usually is just hauled away.

  "It's not economical enough to split it back out and try to reuse it. So you recycle these things in a manner that is most economical for you," the source adds.

  Products like sandwich cookies present a different problem. As separate components, the base cake and filling can be reworked into their parent product. But when combined, differences in their ingredient content affect further production. Fat types are different in each section, and while the basecake is made from regular granulated sugar, the creme uses 10% powdered sugar, affecting spread and making it impossible to rework. Often products that can't be reworked but are still sanitary and edible can be sold as animal feed for a smaller profit, rather than having the manufacturer pay exorbitant hauling fees.

  Some products are actually formulated to accommodate rework. Initial production trials afford some idea of how much scrap a new product will generate, and give product designers time to create a formula that allows for rework. Other products can be reformulated without changing their characteristics or integrity. Some cracker manufacturers have substituted upwards of 5% to 10% of their flour ingredient for cracker crumbs ground from cripples, and one confectionery manufacturer found that adding rework actually improved production.

Waste not, want not

  Ironically, when a product relies on rework, an efficient line can have negative results. While it seems high, one East Coast-based baker tries to maintain its cripple count at about 5% to assume the same control over every batch. But that kind of consistency in creating scrap or damaged product isn't always possible, nor is it necessarily what management considers good practice.

  When a line is running at peak efficiency, those manufacturers who require a specific percentage of rework in their product are forced to buy or trade cracker crumbs with another production facility in order to keep the line running.

  It's also a matter of checks and balances, says one industry source. "What usually happens is the ebb and flow of line efficiency means that now and then you'll get a backlog of rework. You can either throw it away or store it for a time when you're lean on scrap. As long as it's not for a very long period of time, it makes up for the times when the line is running efficiently," he says.

  Sources say that product set aside for rework should be given the same priorities and quality control as any other product. Keep a check on how much you can reasonably store and use in a limited amount of time. Those products that have already been processed may have a longer shelf life than fresher ingredients, though the reactive properties of one ingredient may affect another.

  According to Zelch, there are no federal regulations specific to products destined for rework. Problems occur when the ingredients in scrap or damaged product do not conform to those listed on the ingredients legend of the product for which it is intended. At that point, he says, it falls under the domain of the Food and Drug Administration. So, for example, buns should be used for bun dough and breads for bread dough.

  One of the main concerns associated with any type of rework is its turnaround time. Fresh products such as dough should be turned around immediately for sanitary reasons and product integrity. Bread dough that's been sitting around the warm floor for as little as 10 minutes can create pockets in a new batch. Fermentation also occurs during this period, promoting the growth of wild yeast that can affect the fresh product, as well as break down the consistency of other products in a matter of hours.

  "Control of wild yeast is No. 1 here at AIB," says Doerry. "Because once you get wild yeast, you perpetuate it. So you should clean up at least once a week and clean your retarder at least once a week, even if you have to throw some of the scrap out. The moral of the story is keep your scrap as low as possible and turn it over as fast as possible."

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