Shelf Life Considerations and Its Impacts on Regulation and Standards

Food Regulations and Labelling Standards Conference 2015PARKROYAL Darling Harbour Sydney

Professor Todor VasiljevicDiscipline Group Leader Food, Nutrition & DieteticsCollege of Health and BiomedicineVictoria University

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Presentation outline

• What is shelf life?• Factors influencing shelf life • Quality indices for testing shelf life • Determination of shelf life• Approaches to determine shelf life• Steps to design a shelf life study• ASLT• HACCP• Regulations and standards management through the

food chain• Impacts of shelf life on food safety

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What is shelf life of food products?

• Period of time for which a particular food product remains safe and suitable for consumption

• No sign of any types of deterioration in quality• No spoilage condition - unacceptability to consumers• No food safety issue - illness to consumers• No formation of toxic products within the food• No loss of significant nutritional content (e.g. vitamin content) - no

longer meet declared nutritional value• Should not cause food poisoning due to pathogenic growth or toxins

production in the food during storage• No sensory quality deterioration (e.g. colour, flavour, texture, aroma)

– As a whole, shelf life must accommodate safety, quality, organoleptic & appearance requirements to ascertain customer acceptance of the food product

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What is shelf life?

• Shelf-life related definitions:

– Used by date: used for products, which from a microbiological viewpoint, are highly perishable and are therefore likely, after a short period of time, to affect consumers’ health

– Best before date: reflects the quality (e.g. taste, aroma, appearance) rather than microbial or chemical safety of a food product

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What is shelf life?

• A balancing act based on food safety management system, including:

– Consistency in raw materials & formulation

– Proper application of processing/operation steps and handling

– HACCP (Hazard Analysis Critical Control Points)

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Chief factors influencing shelf life of foods

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Intrinsic Factors Extrinsic Factors

Nature and quality of raw materials Processes applied to food

Product formulation – inclusion of preservatives or not

Conditions during distribution, storage, retail display and storage by consumer

Product biological structure Cooling methods

Water activity and moisture content Types of packaging

pH and acidity Storage temperatures

Oxygen availability and redox potential Light exposure

Initial microbial load Freezer burn

Fat, oil, alcohol content Relative humidity

Maillard reaction Mechanical stress

Table 1

Quality indices for testing shelf life of food products - physical changes

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Quality indices - Chemical changes

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Quality indices –Microbiological changes

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Quality indices- Sensory quality changes

• Changes in

– Texture

– Appearance

– colour

• Development of off-flavour

• Hedonic testing – model progressive loss of overall quality characteristics – graded hedonic scale

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Examples of marker chemicals produced in food by insects and microbial activity which can be used as quality indices

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Food product Chemical Spoilage problem

Prawn Dimethyl-trisulphide, indole Rotten onion-like

Fish Trimethylamine Off-flavour, loss of freshness

Cocoa powder (packaged) Chlorinated anisole Muddy

Canned products, vegetables, fruits, meat, fish and dairy products

n-Butyric acid (volatile fatty acids)

Swelling of low-acid canned foods

Fruit juices D-alanine (> 1 ppm) (presence of D-alanine)

Quality indicator

Table 2

Deterioration mechanisms for some food products

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Food Product Type of spoilage Critical storage variables

Fruit and leafyvegetables

Enzymatic softening, microbial growth, bruising, moisture loss/wilting

Temperature, light, oxygen, handling, humidity

Fresh fish and seafood Microbial growth, oxidation Temperature, oxygen

Milk and dairy products Oxidation, hydrolytic rancidity, bacterial growth, lactosecrystallization

Oxygen, temperature

Bread, cereals, soft bakery products

Moisture migration, starch retrogradation, microbial (mould) growth, oxidation, breakage

Humidity, temperature, oxidation, handling, light

Chocolate Sugar and fat crystallization (sugar and fat bloom), oxidation

Humidity, temperature,oxidation

Frozen foods Oxidation, freezer burn, ice crystal formation, texture change

Oxygen, temperature, humidity

Coffee/tea Oxidation, volatile loss Oxygen, light, moisture

Table 3

Maillard reaction (MR)• Non-enzymatic browning

• Interactions between free or protein-linked amino acids and reducing sugars

• Impacts on sensory and nutritional characteristics of foods

• Production of CO2 – formation of aldehydes – unpleasant sensory properties + nutritional loss

• Lipid autoxidation

• Factors affecting MR:

– Structure of amino acids and sugars

– Temperature

– pH value

– aw

• Some food products susceptible to spoilage/staling due to MR:

– Fruit juices

– Dairy products

– Beer and lager

– Coffee

– Confectioneries

– Roasted peanuts

– Bread21/07/2015 13

Determination of shelf life

• No universal protocol

• Questions arise when designing a shelf-life study:– Proper food samples storage

– Testing time

– Quantity of samples

– Quantity of tests to be applied

• Key steps for designing a shelf-life study:– Duration of time of the study

– Sampling frequency

– controls regarding microbiology, sensory and physico-chemical analysis

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5 approaches to estimate shelf life• Literature values

– Published data based on the US Army and Labuza

• Distribution turn over– Requires no testing

• Distribution abuse test– Based on distribution and home storage conditions

• Consumer complaints– R&D scientist analysed consumers’ complaints to improve products– Can be used in conjunction with any of the above mentioned methods

• Accelerated shelf life testing (ASLT) based on Arrhenius model– Examine product periodically until end of shelf life occurs– Use these results to project the product shelf life under true distribution conditions– ASLT conditions should be chosen properly– Appropriate algorithms for extrapolation are used– Shelf life and safety of minimally processed CAP/MMP chilled foods – Aspartame stability in commercially sterilized flavored dairy beverages– ASL testing of whey proteins coated peanuts

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Steps to follow for designing a shelf life study

1. identification of the main causes of food spoilage

2. planning the shelf life study1. Which type of analyses to be carried out?2. How many analyses must be carried out?3. How many samples need to be withdrawn per

analytical point?4. Which period is the most appropriate to perform the

study?

3. shelf-life establishment4. shelf-life monitoring

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Accelerated shelf life testing - ASLT• General equation describing quality loss in food

system may be expressed as follows:

– rQ = ɸ(Ci, Ej)

This equation puts in mathematical form, the fact that the rate of quality degradation, rQ is a function of a number of compositional factors, Ci, such as concentration of reactive species, MO levels, pH, and aw

as well as environmental factors (E), including temperature, relative humidity, light, mechanical stress and pressure.

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Effects of temperature on shelf life of foods• Reaction rates increase with increasing

temperatures

• Arrhenius relation– Describe effects of temperature on the rate of several

reactions of quality loss

𝐾 = 𝐾𝐴𝑒𝑥𝑝−𝐸𝐴

𝑅𝑇

KA = Arrhenius equation constant

EA = joules or calories per mole (activation energy)

R = universal gas constant

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Arrhenius relation

• Alternative to Arrhenius law to describe temperature dependence of reaction rates is through the Q10 concept

– Ratio of the reaction rate constants at temperatures differing by 10oC or equivalently, it shows the reduction of shelf life, when the food is stored at a temperature 10oC higher

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HACCP safety assurance systems

• Hazard Analysis and Critical Control Points (CCPs)

• International recognition

• Most effective way to ensure food safety

• Adopted and amended by the Codex Alimentarius Commission

• Provides preventative control of major food safety hazards– Reducing reliance on end product testing

• Consists of 7 principles

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Application of the HACCP 7

Principles

1. Conduct a hazard analysis and

validation of such hazards

2. Determine the CCPs

3. Establish valid critical limits

4. Establish and/or formulate a system to monitor control

of CCP

5. Establish corrective actions when CCP is not

under control

6. Establish procedures for verification to

confirm that the system is working

effectively

7. Establish documentation concerning all procedure and

appropriate to these principles and their

application

Figure 4

Regulations and standards management throughout the food chain

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The Food Supply Chain

21/07/2015 23Figure 5: The food supply chain

Regulations and standards management throughout the food chain• Food regulations aim at:

– Protecting consumers’ health and well being– Increasing economic viability– Maintaining fair trade within and between nations– Assuring safe and continuous supply of commodities– Eliminating fraudulent practices

• World Health Organisation (WHO):• Established in 1995• Deals with the rules of trade between nations• Administering trade agreements• Reviewing national trade policies• Cooperating with international organizations

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Regulations and standards management throughout the food chain

21/07/2015 25Figure 6: The pyramid of food law

Regulations and standards management throughout the food chain

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- Dairy Australia -

• Food Standards Australia New Zealand (FSANZ)• Australian Pesticide and Veterinary Medicines

Authority (APVMA)– Determines types of chemicals used for the

production of stockfeed & veterinary chemicals used for treatments of animals

– Stockfeed and grains industries should have their HACCP based accredited QA programs

– Chemicals registered by APVMA, only, are allowed

• Department of Agriculture (DoA)• Animal Health Australia (AHA)

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Australian key federal agencies

Important regulations for the Australian dairy industry

• The Food Standards Code

• Export Control Act 1982

• Export control (Prescribed Goods – General) Order 2005

• Export Control (Milk and Milk Products) Order 2005

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Farm regulation

• Australian dairy farms – documented food safety programs (FSP) – approved by State Dairy Food Authorities (SDFAs) –grant farm licence

• Key elements of FSP:– Control of contaminants: physical, chemical & microbiological

– Dairy milking premises

– Hygienic milking

– Water supply and quality

– Cleaning and sanitising

– Traceability and records

– Personnel competency

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Transport regulation

• Milk transport operators – documented FSP

• Key elements of FSP:

– Control of food safety hazards during collection and transport

– Product traceability

– Time & temperature controls – minimize food safety risks

– Personnel skills & knowledge

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Manufacture regulation

• Factories manufacturing product for export require DoA registration• Core elements of FSP:

– Pathogen reduction technologies including pasteurisation– Temperature controls– Cleaning and sanitising– Storage– Traceability forwards and backwards through supply chain from farm to

customer– Post-pasteurisation hazard management– Raw material and ingredient management– Records– Personnel competency

• Product recall system – FSANZ product recall protocol• Australian Milk Residue Analysis Survey (AMRAS) – monitor safety of milk

& milk dairy products

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Distribution regulation

• End product – stored in warehouses operated by the dairy company or external contractors

• Warehouses – licenced by SDFAs

– Registered by the DoA for exporting dairy products

• Key elements of FSP:– Prevention or control of potential hazards to food

safety

– Identification and traceability of product

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Markets regulation

• FSANZ Food Standards Code covers all food products either manufactured within Australia or imported.

• All manufacturers, wholesalers, distributors and importers of food are required to have in place a written recall plan modelled upon FSANZ Product recall protocol

• DoA- competent authority for export inspection and certification

• Export regulations cover the following requirements:– Importing country’s food safety requirements– Product standards– Biosecurity– Quarantine standards and traceability

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How shelf life impacts on food safety?• Food safety is an integral part of food security

• The most effective way to ensure food safety is to meet the internationally recognised HACCP system as adopted by the Codex Alimentarius Commission and written into legislation in countries like Australia.

• FDA labelling requirements

• USDA - ensures food safety throughout the food chain

• USDA, FDA & WHO implementing standards on the hygienic methods of food handling and processing

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Food safety

• Food safety is a shared responsibility between governments, industry, producers, academia and consumers

• Achieving food safety is a multi-sectoral effort requiring expertise from a range of different disciplines:– Toxicology– Microbiology– Parasitology– Nutrition– Health economics– Human and veterinary medicine– Education

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How shelf life impacts on food safety?

• Different factors affect the safety of food and lead to variation in shelf-life

• Primary objective when estimating shelf life is to maintain food safety

• Predicting realistic shelf life for a food product is crucial to minimize risk of food safety issues

• Good manufacturing practices (GMP)

• Good hygiene practice (GHP)

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Maintaining food safety and setting and validating food shelf life

How shelf life impacts on food safety?

• Packaging– Food packaging provides an element of food quality

within its shelf life. – Packaging materials and labelling are regulated by

the FDA– Australia: Food Standards Code – Standards 1.4.1

Contaminants and natural toxicants specifies “maximum permitted concentrations for metals as well as vinyl chloride and acrylonitrile. Packaging materials must not leach into the food more than the specified limit for the contaminant in this standard”–this may impact on shelf life and thus posing a food safety issue.

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How shelf life impacts on food safety?

• Harmful bacterial are becoming resistant to drug treatments

– Antimicrobial resistance – growing global health concern

– Overuse and misuse of antimicrobials in agriculture and animal husbandry – leading to emergence and spread of antimicrobial resistance

– Antimicrobial-resistant bacteria in animals may be transmitted to humans via food

- This impacts on food safety and consumers’ health -

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Prof Todor Vasiljevic

College of Health and Biomedicine

Victoria University

PO Box 14428, Melbourne VIC Australia

PHONE +61 3 9919 8062

EMAIL todor.vasiljevic@vu.edu.au

WEB vu.edu.au/research/afs

CONTACT DETAILS

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