Food Packaging of Dairy Products

Packaging of Dairy Products

Fluid Milk – Pasteurized Milk

Liquid Milk for consumption MUST be pasteurized and before it is packed

Generally only 90-99% of microbes in milk are destroyed by pasteurization

Fluid Milk – Pasteurized MilkPHTC

(Post Heat Treatment Contamination)A cold-tolerant Gram-negative spoilage bacteria affects the shelf-life of

commercial pasteurized milk at refrigerated storage temperatures.These bacteria are completely inactivated by pasteurization

BUT with inefficient sanitation of milk contact surfaces and contamination from dairy plant atmosphere – can be regularly found in pasteurized milk

Fluid Milk – Pasteurized Milk

Shelf-life of Pasteurized Milk – depends on the activity of heat-resistant organisms

Typical Shelf-life 8-10 days at

Realistic Shelf-life18-20 days at

Fluid Milk – Pasteurized: Temperature

ThermizationThis is to delay spoilage of milk during storage

before pasteurizationUsually for cheese production

Its insufficient to destroy bacterial pathogens but will destroy bacteria (psychotrophs)


PasteurizationLTLT method or Holder Process

HTST method

After being subjected to heat the milk is cooled immediately


Ultrapasteurization(Extended Shelf-life or Superpasteurized)

Destroy all pathogenic organisms

“Products that have been treated in a manner to reduce the microbial count beyond normal pasteurization, packaged under extreme hygienic conditions and have a

defined prolonged shelf-life under refrigeration conditions”

helf-life of up to 90 days

Fluid Milk – Pasteurized: Shelf-life

Most critical factors affecting the shelf-life of pasteurized dairy products is the temperature of storage

Shelf-life of pasteurized milk is determined by the level of contamination with Gram-negative psychrotrophic bacteria

Spoilage at refrigeration temperature – growth of Pseudomonas spp.

Fluid Milk – Pasteurized: Effect of Light

CHEMICAL REACTIONS INDUCED IN MILK BY LIGHT

flavor changes, loss of vitamins and other nutritional components

Wavelengths ranging from 420-550 nm

Fluid Milk – Pasteurized: Gases

OxygenImportant role in the light-induced development of off-flavors

Addition of Carbon dioxideInhibits growth of bacteria

Extends the shelf-life under refrigeration

Fluid Milk – Pasteurized: Packaging Materials

Traditionally Packaged in refillable glass bottles

TodaySingle-serve paperboard cartons and

plastic containers

I. Fluid Milk – UHT MilkUHT Milk

“Milk which has been subjected to continuous –flow heating process at a high temperature for a short time and which afterwards has been

aseptically packaged”

Fluid Milk – UHT Milk

Process DescriptionSterilization

UHT can be classified either directly or indirectly heatedPackaging

Aseptic Packaging Most widely used are paperboard, alufoil, plastic laminate carton and

plastic container

Fluid Milk – UHT: MicrobiologySPORE CAPABLE OF SURVIVING UHT PROCESSING

Geobacillus stearothermophilusBacillus subtilis

Bacillus megateriumBacillus sporothermodurans

Paenibacillus lactis

HHRS or HRSHighly heat-resistant spore former

Fluid Milk – UHT: Nutrition

Reduction of Nutritive Value can occur:1. During UHT treatment2. During Storage after packaging

Temperature, Initial Oxygen Content and Nature of the Packaging MaterialPlays a Function in Nutrient Loss

Unaffected Components Affected Components

Fat, Fat-soluble Vitamins, Carbohydrates, and Minerals Water-soluble Vitamins, Proteins

Fluid Milk – UHT: NutritionVitamins

Are more stable under UHT processing conditions

Unaffected AffectedFat-soluble Vitamins (A, D and E)

Water-soluble Vitamins (Riboflavin, Nicotinic Acid and Biotin)

Heat Stable

Folic Acid, Vitamin C and B12

Limited amount of oxygen, ascorbic acid loss is minimal

Fluid Milk – UHT: NutritionVitamins

DETERIORATION DURING STORAGE IS DEPENDENT ON

Oxygen Levels low oxygen levels can be achieved by effective oxygen barriers

Temperature

Exposure to Lightuse of opaque containers

Fluid Milk – UHT: NutritionProteins

This undergoes greatest change during UHT processing and storage

Alterations is related to flavor, gelation, sediment formation, fouling of heat transfer surfaces, loss of nutritional value and browning

Severe heat treatment cause up to 80% denaturation

Fluid Milk – UHT: Biochemical and Physical Aspects

PROTEASES & LIPASESGreatest concern

Shelf-life of UHT milk is limited by age gelationOnce the milk has gelled it’s the end of its shelf-life


FACTORS AFFECT THE RATE OF GELATION

ProteolysisSeverity of Heat Treatment

Storage TemperatureBacteriological Quality of the Milk

Milk Solids Content


Preventing Gelation

Use of High Quality Raw MilkIndirect Heating System

Addition of Sodium Hexametaphosphate (SHMP)

Fluid Milk – UHT: Flavor

Fresh UHT milk is characterized by a poor flavor, noticeable “heated” flavor and a sulfurous odor

Oxidized or rancid off-flavors develops depending on the level of oxygen and storage temperature

Fluid Milk – UHT: Packaging Materials

Most common is paperboard laminate carton

Fermented ProductsFermented Milk

Products from milk homogenized or not, pasteurized or sterilized and fermented by means of specific microorganisms

Fermented ProductsYogurt

The most important of the fermented milk productsKefir Koumiss

Alcohol content of 0.5-2% Alcohol content of 2-3%Contains carbon dioxide, formed by heterofermentative, aroma-

forming lactic acid bacteria

Fermented Products – Packaging Materials

Butter and Spreads - Composition

ButterA fat obtained from milk

80-82 % Milk Fat Content2 % Total Fat-free Dry Milk Solids

16 % Moisture Content

Butter and Spreads - Production

MILK FAT IS CONCENTRATED BY:1. Separation of the milk2. Churning of the cream

Butter and Spreads - ProductionClassifications of Butter1. Unsalted Butter – prepared from sweet cream2. Salted Butter – has a salt content of 0.2-2 % prepared from sweet cream3. Unsalted Butter – prepared from sour cream4. Salted butter – prepared from sour cream

Butter and Spreads – Shelf-lifeINFLUENCED BY

Microbial, Enzymatic and Chemical ReactionsSusceptibility to readily absorb odors

Natural Antioxidant in ButterTocopherol (Vitamin E)

Butter and Spreads – Packaging Requirements

OxidationButter is very susceptible to light-induced flavors

Degree of Deterioration depends onLight source, wavelength of light, exposure time, distance and beta-

carotene content


Water Vapor PermeabilitySurface desiccation of butter results to discoloration

(primrosing)


Odor Permeability

Satisfactory Packaging Material Protect the butter from odor compounds


Packaging in Current Use

RETAIL PACKAGING OF BUTTER

Aluminum foil laminated either to greaseproof paper or vegetable parchment or paper alone

OTHER TYPES

Plastic tubs