肉制品中水分活度检测方案(水活度分析仪)

BY DECAGONDecagon Devices2365 NE Hopkins CTPullman， WA 99163509-332-5587sales@aqualab.com@2013 Decagon Devices， Inc.PRINTED IN THE USA Water ActivityandShelf-StableMeat Products How to Profit from this RequiredMeasurement F AQUA 'LAB Water activity. You have to measure it.But you can also profit from it， and this guide will show you how. SDA inspectors expect to see wateractivity as a critical control point (CCP)in HACCP plans， typically during dryingand packaging. A water activity below 0.85 is an FSISregulatory requirement for shelf stabilityaccording to HACCP Model 10-GenericHACCP Model for Heat Treated， Shelf StableMeat and Poultry Products. Other moisture measurements， includingMPR and moisture content， are"not safetyconsiderations" and aren't included inHACCP plans. The USDA explains，“Product water activityis best correlated to inhibition of eachpathogen's growth." But why? Locking Up Water Let’s look at this in more detail. Listeria， E. Coli， Staph， and Salmonella are tinyorganisms， and like any organism they needwater to grow and reproduce. They get that water by sucking it in throughthe cell membrane that surrounds them. This suction power comes from energydifferences between the water outside andthe water inside the cell. How Water Moves It’s easy to see that water moves from high to low energy： picture molecules from highenergy boiling water steaming into the lowerenergy atmosphere. Energy differences between a cracker and apiece of cheese are less extreme， but as thecheese sits on the cracker， water molecules willmove from the cheese， in which the water hasa higher energy， to the cracker， in which theenergy is lower. This principle holds true at the molecularlevel too， and pathogenic bacteria use it topull water from the higher water energyenvironment outside the cell to a lower waterenergy environment within the cell.Creating Osmotic StressIf you lower the water energy outside the cellenough， it causes "osmotic stress"： the cellcan't take up water and becomes dormant.Osmotic stress doesn't kill pathogenicbacteria， it just makes them unable toAs Marianski so vividly puts it in The Art of reproduce. Water activity is simply a measureMaking Fermented Sausages， controlling water of the energy status of water in a material.activity "is like stealing food from the bacteria." You can use it to see if the water in a piece ofLowering water activity "locks up"water， jerky has enough energy to support a particularultimately making it impossible for bacteriato reproduce.Different pathogens cope with osmotic stressin different ways. That’s why Staph， say，is able to survive at lower water activitiesthan Listeria. strain of bacteria. Control Microbial Growth Lowering water activity doesn't kill bacteria，but after a kill step like heat treatment，water activity will control bacterial growth，and that’s why it's the FSIS’s moisturemeasurement of choice. It can be much more，however. Water activityhas significance beyond FSIS， the FDA， andHACCP. It’s a powerful way to measure andunderstand water in your product. Moisture Super-Spec There's a guy in our office who likes his jerky tobe just a little tougher than old shoe leather.Most other people in our taste tests preferreda moister， more easily chewed product. Only you know your market and the textureyou're aiming for. But water activity specsshould be part of your recipe for consistency.Because once you've identified the wateractivity sweet spot--the point at which yourjerky is safe and savored--you want to turn thatpoint into a moisture super-spec. Right Every Time The beauty of water activity is that you actuallyknow when it's done--done right--and you candry to that exact point every time. ·you can measure during drying to makesure that each batch reaches that point ·you know you have satisfied safetyrequirements ·you know that you are not over- or under-drying your product A Quick and Easy Measurement Traditional moisture content measurementsare nearly impossible to make during thedrying process.Water activity can be measuredat the line in 5 minutes or less. A Test Anyone Can Run If you can microwave a burrito， you canmeasure water activity to 0.003 aw. Really. No science degree required. Consistency Batch to Batch Unlike other moisture measurements， wateractivity is standards based.This makes iteasy to comply with HACCP procedures thatrequire verification， and it also makes it easyto compare values from batch to batch，between processing locations， and evenbetween suppliers and buyers. It's beautiful：a moisture number tied to safety on one sideand standards on the other. Prevent Losses from Over-Drying In product testing， we found that over-dryingjerky is easy to do if you don't monitor wateractivity. Even small variations have an effecton quality and profits. In fact， we found thata small difference in water activity spec waslike tossing a quarter into each bag of jerkybefore shipping. You can calculate what inconsistency in dryingcould be costing you. www.aqualab.com/over-drying Strategies for a Safe Product We tested a wide variety of shelf stable meatproducts in our lab. These products werecontrolling water activity using a number ofdifferent humectants， including salt， soy sauce，and sugar. Only one contained glycerine， avery common humectant. As these products show on the back coverchart， there are many strategies you can use toget to a safe water activity. Sophisticated Formulation This guide is about the basics of water activityand shelf-stable meats. If you're interested，you can go much deeper in understanding andcontrolling moisture in your product.For example： ·learn how to control water activity byadding humectants (salt， sugar， soy sauce) ·model what happens when you varydrying time and temperature ·determine the shelf life of your product ·understand what happens if a productis stored at high temperaturesor humidities · evaluate packaging materials andunderstand the interaction betweenpackaging and shelf life ●·discover how wetting up or drying outyour product affects its water activity Water activity of Processed Meats Brand Type % Moisture Water Activity Hormel (Refrigerated) Italian Sausage Crumbles 51.18 0.9714 Old Wisconsin (Refigerated) Turkey Sausage Snack Slices 55.02 0.9404 Jack Link's Beef Steak Tender Bites -Teriyaki 37.45 0.8664 Dissmore's Grocery Store Beef Jerky 40.66 0.8655 Great Value Beef Steak- Sweet Bourbon BBO 36.07 0.8524 Jack Link's Chicken Nuggets-Flamin' Buffalo 40.51 0.8344 Bridgford Pepperoni (slices) 25.89 0.8344 Great Value Beef Jerky- Original 32.37 0.8336 Primal Spirit Foods， Inc. Primal Strips- Hot & Spicy 26.04 0.8309 Jerky Direct Natural Buffalo Jerky-Original 24.9 0.8286 Jack Link's Turkey Jerky-Original 28.52 0.8221 Oh Boy!Oberto Original Beef Jerky 27.7 0.8198 Oh Boy! Oberto BBQ Pork Jerky 23.55 0.8151 Slim Jim Slim Jim Twin Pack-Original 17.23 0.7903 Jerky Direct Organic Beef Jerky-Teriyaki 25.59 0.7899 Sweet Baby Ray's Beef Jerky-Original 25.05 0.7836 Jack Link's Beef Jerky-Original 28.4 0.7768 Matador Beef Jerky-Original 27.19 0.7764 Oh Boy! Oberto Bacon Jerky 18.58 0.7542 Jack Link's Jerky Chew-Original 29.46 0.733 Tillamook Country Smoker Pepperoni Stick-Original 11.06 0.7094 SnackMasters Natural Salmon Jerky-Original 16.43 0.7094 Tillamook Country Smoker Beef Jerky-Old Fashioned 20.13 0.6701 SnackMasters Natural Ahi Tuna Jerky - Original 14.74 0.6069 Tillamook Country Smoker Beef Jerky Slab 13.95 0.5798