1. Dynamics of Food Quality

Perceiving food quality

• Food products as such have no quality

  • Products have properties which are perceived by the consumer as quality

What is perceived quality made up of?

Intrinsic attributes

• Are inherent to the physical product

• These attributes can be noticeable (e.g. taste or texture) or otherwise objectively determined (e.g. safety or health)

• They are the result of physicochemical and other properties of the product (e.g. pH, microbial load).

Extrinsic attributes

• Do not necessarily have a direct relationship with the product properties, although they can still change the perception of the consumer of the quality of the product.

• These extrinsic attributes relate to the production and marketing aspects of the product and can therefore influence the acceptability of the product (e.g. animal welfare, sustainability).

Physicochemical properties and technological properties

• influences both intrinsic and extrinsic quality attributes

• Moreover, the personnel involved in food product affect the technological properties by their behavior

• The legislation affects quality attributes by putting restrictions and requirements on the production properties, technological properties, and managerial aspects.

Mavlow’s hierachy of needs

Food properties: Safety

• Safety: absence of hazards

• Risk: chance of presence of hazard & severity of harm

• Acceptable risk?

• Can be microbial, chemical or physical

Food properties: Shelf life

• Shelf life: time between production & point at which it is no longer fit for consumption

  • Safety - e.g. pathogens

  • Spoilage - e.g. spoilage bacteria

  • Nutritional value - e.g. vitamin C decline

• Types of changes: microbial, chemical, enzymatic, physical and physiological

Food properties: flavor

• Safety & shelf life are often taken for granted, whereas flavor is an essential element in satisfaction with a product

• Flavor is observed with all five senses:

  • Sight

  • Smell

  • Touch

  • Taste

  • Hearing

Food properties: convenience

• Convenience is related to ease-of-use

• Related to packaging, but also pre-processing so that preparation at home can be convenient.

Food properties: health

• Starts from basic need of macro- and micronutrients

• Also related to health-promoting/bio-active ingredients

• As overeating is a major problem nowadays, also satiety/satiation is important for the consumers’ health

Food properties - extrinsic attributes

What are the three aspects of food quality?

1. Linking properties of to food quality

2. Dynamics of food quality (food quality is not constant!)

3. Food quality throughout the production chain

What are the five types of dyanimc food processes?

Primary production - animal production (farming practices)

The three main quality influencing factors for animal production are farming practices, transport, and slaughtering.

• "Farming practices" is a term covering a lot of different parameters describing the conditions on the farm. Factors like safety and flavor are strongly influenced by the farming practices.

  • Some of the conditions on the farm influencing final product quality are breed, keeping, feed and animal health.

  • “Keeping” situation of the animal can also influence quality in terms of hygiene. Problems with hygiene can lead to food safety/shelf life problems. (e.g. udder cleanliness)

  • “Feed” Influences the quality of the animal product through the amount as well as the quality of the feed given to the animal.

    • The amount and quality of milk/eggs/meat produced by an animal is directly related to the feeding regime on the farm.

  • “animal health” can influence the quality of animal products. E.g. mastitis (udder infection) in cows will signficantly reduce both the quantity and quality of the milk produced.

Primary production - animal production (Transport and slaughtering)

• Transport of live animals is an important step, because stress of animals will significantly impact the quality of the meat.

• Also stress during slaughtering can cause quality problems.

• This stress can be reduced during transport by easy climbing into the truck, medium journeys (not too short, not too long) so that the animals have time to calm down.

• Hygiene in the slaughterhouse is also important for food safety.

Primary production - vegetable production

Three important steps in vegetable production are the cultivation, harvesting practices and post-harvest practices.

• “cultivation” The choice of seed to cultivate can depend on what can grow best in local area or on consumer demands.

  • The quality of cultivation depends on timing, supply of nutrients through fertilization, supply of water, use of herbicides and pesticides

• “harvesting practices” Harvest time and mechanical injury are two important aspects of the harvesting process which should be well controlled to have an optimal product quality.

  • Harvesting should occur at right maturity, mechanical injury can occur during harvest.

• “Post-harvest practices” refer to practices in both transportation and storage that take place after harvesting the fruits and vegetables

Food processing factors

• Storage of raw materials

• Processing

  • Preparation

  • Fermentation

  • Separation & combination

  • Heating

  • Evaporation and drying

  • Extrusion

Food processing - process

• Preparation: Includes sorting, cleaning, cutting. Hygienic design of preparation process is imporant

• Fermentation: When beneficial microbes grown in the food product. Increases shelf life, changes flavor and other quality attributes.

• Separation & combination: When food is split in ingredients or ingreidients are added to foods.

• Heating: Ensures the safety of the consumer and increases shelf life.

• Evaporation & drying: stabilizes the food. Aims at reducing growth of bacteria, but may also be used to limit degradation reactions.

• Extrusion: Used for e.g. pasta and is a combination of heating and drying.

Three aspects of packaging

• Protection: food product should be protected against unwanted contamination from the environment.

• Convenience

• Labelling

Retial & consumer

• Critical factors at the retailer which influence the product quality are time-temperature of storage, and hygienic conditions.

• After buying the food product, the control over the treatment is in the hands of the ocnsumer.