Procedures & Guidelines Procedures for Production Chocolate Milk Beverage FSQ-588015-0101 of UHT Table of contents Introduction .2 Raw Material 2.1 Impact of the raw material on the quality of the final product 2.2 Guide for Thermoresistant Spore count 3 Processing .3 3.1 Ingredient blend 3.2 Pre-treatment .3 3.3 Heat treatment .4 3.4 Flowchart FSQ – 588015-0101 i Procedures & Guidelines Procedures for the Production of UHT Chocolate Milk Beverages Introduction With the exception of milk powders several other dry ingredients are used in the production of chocolate milk or milk-based chocolate beverage such as: Cocoa Powder Whey Powder Sugar Stabilizer Raw materials can have high loads of bacteria in dormant state called spores These spores not show metabolic activity and they survive highly unfavourable environmental conditions, such as heat, dehydration, cold, poisonous substances and radiation If thermoresistant spores survive the UHT process they can germinate into vegetative cells and begin to grow, causing spoilage of the final product This document describes/provides…: • how to efficiently rehydrate dry ingredients in order to maximise/optimise heat penetration during processing • the pre-treatment process, which will minimise the risk of bacterial growth, • the normal range of parameters used, • a typical flowchart for easy reference, …in order to reduce the spore load during processing of chocolate milk or milk-based chocolate drinks Raw Material 2.1 Impact of the raw material on the quality of the final product The objective of the UHT processing is to achieve commercial sterility The efficiency of the UHT process depends on: • Initial load of bacterial spores • Thermal resistance of bacterial spores present • Process parameters: time and temperature to which the microorganisms are exposed during the UHT process The efficiency of the UHT processing is expressed as the number of decimal reductions of thermoresistant spores Therefore an acceptable level of defects should be established to rate the quality of the final product The maximum acceptable defect rate for such products varies from 1:1000 to 1:10000, i.e one defect (process survivor) in 1000 or in 10000 units produced FSQ – 588015-0101 Procedures & Guidelines Procedures for the Production of UHT Chocolate Milk Beverages 2.2 Guide for Thermoresistant Spore count As the raw material plays a very important role in the maximum rate of defects in the final product, the quality of all raw materials should be guaranteed regarding the load of mesophilic and thermophilic spores However it should be pointed out tha t even sporeformers with a lower heat resistance can be problematic in processing conditions where there is no adequate mixing and soaking during the pre-processing phase Therefore the figures given in the table below can only be seen as a very rough indication of what should be recommended in terms of spore load based on a log reduction during processing: Guide for Thermoresistant Spore count in UHT processing* (Sample taken from balance tank of sterilizer) Spores Objective Action Mesophilic Spores Thermophilic Spores 100 cfu/ml 10 cfu/ml 1000 cfu/ml 100 cfu/ml Processability limit 10000 cfu/ml 1000 cfu/ml It is also recommend that the peel content of the powder cocoa is minimised, max1.75% and thinness, 99.5% (80 mesh) * Reference Material: “A practical approach to the detection and enumeration of spore forming bacteria” Note: Standard procedures may be difficult to apply when it comes to sampling preparation techniques for chocolate powder with e.g hydrocolloid ingredients The preparation of documentation about this issue is ongoing Please consult Dr Fritz Lembke; Tetra Pak R&D in Stuttgart for further details Processing Chocolate milk beverage processing usually involves three stages The first stage is blending the ingredients, followed by correct preparation of the product for the last stage – the UHT treatment The quality of the final product depends on the correct fulfillment of those stages 3.1 Ingredient blend Some stabilizers may be difficult to dissolve Therefore, a high temperature, above 60°C is necessary, and a lot of agitation to avoid sedimentation Some stabilizers can achieve good dispersion even under cold conditions as shown in the flowcharts 3.2 Pre-treatment As the cocoa powder consists of fine particle agglomerate around the cocoa butter present in the granule, it is very important to correctly rehydrate the product so that the microorganisms inside the granules can be reached by the thermal treatment It may be favourable that the product undergoes a maturation stage (soaking time), which means keeping the product at to °C for to 12 hours (depending on equipment and raw material quality) under agitation This is recommended so that all the solid ingredients are properly rehydrated After that stage the product can be UHT processed FSQ – 588015-0101 Procedures & Guidelines Procedures for the Production of UHT Chocolate Milk Beverages 3.3 Heat treatment The heat treatments applied to long life products aim to achieve commercial sterility by using different combinations of process temperature and holding time The combination of those variables (temperature x time) determines the intensity of the treatment Concerning products with high spore loads, the treatment should be stricter than the one normally used for milk processing Parameters normally used for the processing of chocolate products are around 137 -142°C for to seconds, but the most appropriate combination depends on the plant configuration FSQ – 588015-0101 Procedures & Guidelines Procedures for the Production of UHT Chocolate Milk Beverages 3.4 Flowchart A typical flowchart for chocolate milk production Weigh the ingredients according to the formulation If the powder cocoa has particles, sift it through a 80 mesh sieve Prepare the slurry by use of 10 - 40 % of water or milk of about 50 55°C and process it in the mixing equipment with the chocolate powder and largest part of sugar Heat the slurry to 80-95ºC for10-30 minutes under agitation Prepare all other ingredients (water, powders, fat) Drymix part of the sugar with the stabilizer Option : Maturation Cool down and store for 2-12 hours at – 6°C (shorter times for liquid products and longer ones for powder products) Use low agitation speed during this step Filtration Use double filter, 180 – 200 mesh = 75 micron UHT treatment With homogenization Aseptic filling Add all the mixes to the blending tank under agitation Pasteurize and Homogenize the batch FSQ – 588015-0101