Water Activity Tools How to Profit from Proven Product-Quality Techniques in Five Quick Lessons Safety & Profitability Intersect Grocery Distribution & Shelf Life Caking & Clumping The Power of Isotherms Moisture Migration

The Importance of Understanding Water Activity It doesn’t cost much to add water to your product. Unless you add the wrong amount, then water can get very expensive. Add too much and your product will mold on the shelf. Get the proportions wrong, and your product could lose its characteristic texture. Combine two ingredients with incompatible water levels and you might get a clumpy mess that gums up the factory machinery. Store a combination of ingredients at unstable moistures and you’ll possibly end up with an ingredient so hard and dried up that it breaks a customer’s tooth and causes a lawsuit....

Scenarios, Science and Solutions Safety & Profitability Intersect Finding the Moisture Super Spec……………………………………………………… 1 Grocery Distribution & Shelf Life Keeping the Cake Fresh…………………………………………………………………… Caking & Clumping A Soup Mix Story…………………………………………………………………………… The Power of Isotherms Pecans & Airbags…………………………………………………………………………… Moisture Migration Fruitcake & Fruit Cereal Surprise…………………………………………………………

Safety & Probability Intersect Finding the Moisture Super-Spec QA/QC Specs are a critical part of every operation. Where do you set the standard? How much of a safety margin do you need? Scenario Too many manufacturers measure moisture content and use a by-guess-and-by-golly standard. For example, a pet food manufacturer we know was producing to 8% moisture content. Why? Because at that level, he had never had spoilage problems or shelf life concerns. He had a safe product. But he discovered that he was over-drying, producing a lessappreciated and less profitable product. Science Many manufacturers...

Critical control point for stable shelf life Solution When he decided to switch to a water activity spec, he discovered the power of a moisture number tied to both quality and safety. The water activity of his product as originally produced was 0.50 a w. He needed to stay below the mold growth limit of 0.65 a w to produce a quality shelf stable product. Making the product moister also increased its palatability to pets. Without knowing his exact costs, we can still infer the profit margin represented by a difference in 0.50 a w and 0.65 a w . If he produced 20,000 pounds of product per hour,...

Grocery Distribution & Shelf Life Keeping the Cake Fresh Measuring water activity can predict shelf life. Managing it can increase shelf life–and market success. Scenario MOM & POP Bakery baked exceptional cakes. Local demand was high. Mom and Pop wanted to increase sales by expanding. Unfortunately, their delicious cakes had a shelf life of three days. A three-day shelf life left no time to ship the cakes. How could they keep their quality and simultaneously get longer shelf life? Science Once again, water activity to the rescue. Water activity is a well known predictor of microbial growth....

Water Activity & Growth of Microorganisms in Food• Range of Water Actvity Microorganisms Generally Inhibited by Lowest Water Activity in This Range Pseudomonas, Escherlchia, Proteus, Shigells, Klebsiella, Bacillus, Clostridium perfringens, some yeasts Foods Generally Within This Range Highly perishable (fresh) foods and canned fruits, vegetables, meat, fish and milk Salmonella, Vibrio parahaemolyticus, C. botulinum, Serratia, Lactobacillus, Pediococcus, some molds, yeasts (Rhodotorula, Pichia) Some cheeses (Cheddar, Swiss, Muenster, Provolone) and cured meat (ham) Many yeasts (Candida, Torulopsis,...

Caking & Clumping How to mix ingredients without making a mess. Scenario A small dry soup manufacturer was determined to avoid clumped-up soup base. One day he was processing a base with 3% moisture content. He measured some newly received pepper and found it to also have 3% moisture content. Sure that it was safe to mix the two components, he did so and headed out to lunch. The manufacturer returned from lunch, flipped on his processing machinery, and discovered that the whole batch had clumped. He had to throw away the lot. His loss felt even worse as he spent considerable time cleaning up...

Had he measured water activity, he would have found that the soup base had a water activity of 0.28, while the freshly ground pepper measured 0.69 a w . When he combined the two and allowed the mixture to sit over lunch, water moved from the pepper to the soup base and the water activity of the mixture rose above the critical clumping point. Solution The critical point at which a product will cake or clump is product-specific. It can be determined by creating a highresolution moisture sorption isotherm for the product. Maintain the product below that value, and you will avoid clumping. As the...

Pecans & Airbags How a “loss-on-drying” method failed to predict spoilage. Scenario Many manufacturers use the “loss-on-drying” method to measure water content. They weigh the original product, dry it out, and weigh again. A pecan grower sold pecans to a school fundraising organization. Ever year he dried his pecans to a moisture content of 4%. For thirteen years, the method worked perfectly. Year fourteen could have been titled “The Return of the Moldy Pecan.” Misleading because when you measure moisture content, you need to know how dry is “dry enough.” Outside of the safe zone Free of microbial...