Mô tả:
Procedures & Guidelines
Procedures for Production
Chocolate Milk Beverage
FSQ-588015-0101
of
UHT
Table of contents
1. Introduction ...............................................................................................2
2. Raw Material..............................................................................................2
2.1.
Impact of the raw material on the quality of the final product .........................2
2.2.
Guide for Thermoresistant Spore count ................................................................3
3. Processing.................................................................................................3
3.1.
Ingredient blend............................................................................................................3
3.2.
Pre-treatment.................................................................................................................3
3.3.
Heat treatment...............................................................................................................4
3.4.
Flowchart ........................................................................................................................5
FSQ – 588015-0101
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Procedures & Guidelines
Procedures for the Production of UHT Chocolate Milk Beverages
1. 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 do
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.
2. 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
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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 9 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.
3. 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 4 to 6 °C for 2 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
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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 4 to 6 seconds, but the most appropriate combination
depends on the plant configuration.
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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 4 – 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.
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