10 Flashcards
Example of quality defect
Fat bloom: discoloration due to fat crystallization on the surface.
Quality assurance
Involves taking measures to ensure processing steps are performed properly to ensure consistent quality of finished products
Appearance attributes of QC
Color: human eye, spectrophotometer (transparent liquids), tristimulus colorimeter =objectively. Color difference measurements are used because more sensitive, like a standard plate is made to represent desired color. Sophisticated color monitoring tools are much more common and enable product color to be better controlled and quality enhanced.
Viscosity and textural attributes of QC
Rheology: study of the deformation and flow of matter.
Subjective descriptors describe rheological characteristics of a product.
Objectively: for fluids we use Bostwick consistometer to measure the time it takes for a viscous fluid to flow down an inclined plane and numerical measurements can also be used by viscometers.
For solids and semi-solids, we measure texture and not viscosity. We measure the Force required for deformation of a material, like compression, shear, tension or combination (chewing). Also, Instron Universal Testing Machine is used with bunch of accessories to mimic food forces. Texture and viscosity changes over time and processing but we try to keep it as best as possible.
Flavor attributes of QC
Gas chromatography for volatile compounds associated with aroma, conductivity for salt concentration, pH meters for acidity and refractometers for sugar concentration. But no instrument has replaced humans yet so we do consumer taste panels and sensory evaluation
Hidden attributes of QC (non-sensory)
Nutritional value is a type of hidden quality attribute. Best-before date. Accelerated storage trials are conducted to determine best before dates (elevated temperatures). In-house quality considerations impact the final quality like plant sanitation and microbiological quality.
Unit operation definition
Food manufacturing processes subdivisions = unit operations.
Material handling
Harvesting, transport of product to processing plant, pneumatic conveying of powders (flour,sugar) in trucks, bins. Must be carried out under sanitary conditions, minimize losses of raw materials, maintain quality, minimize microbial growth. Liquid nitrogen is used to cool fruits and veggies at harvest. Includes also in-plant conveying of materials like pumping of liquids. Pumps and all other equipment in contact with food require sanitary design.
Cleaning-related operations
All raw materials are contaminated to some degree and require some cleaning operation. Purification of water, evisceration of animals, washing of eggs, removal of mud from oysters, removal of metal fragments from bulk grain with magnetic metal separator. Also includes cleaning of processing equipments, CIP (cleaning-in-place) exist for automated liquid processing equipment, but other types have to be disassembled
Separation-related operations
Solid from solid: peeling of potatoes (most important step), shelling of nuts. Liquid from liquid: separate cream from milk, centrifugation. Solid from liquid: whey proteins from whey. Liquid from solid: pressing juice from fruit, whey from curd
Disintegration-related operations
Reduction in size like slicing of potatoes, grinding meat, milling wheat for flour, homogenization of milk (reduction in fat globule size) filleting of fish.
Mixing related operations
Solid-solid: dry ingredients like soup mix
Solid-liquid: sugar and water like paddles and propeller
Liquid-liquid: oil and water (emulsions) high pressure homogenizers
Gas-solid: incorporate air into ice cream, various types of mixers and beaters.
Heat-transfer related operations
Roasting, cooking, canning, pasteurization, microwave heating, extrusion. Cooling process often have purpose of extending shelf life but not always (ice cream). Includes freezing processes as well
Evaporation-concentration related operations
May require vacuum because of heat sensitivity so we reduce pressure to reduce boiling water to have higher quality
Drying related operations
Reduce water activity and weight.
Forming shaping related operations
Butter, breakfast cereals, chocolates, doughnuts
Packaging related operations
Critical step in maintaining gains achieved by processing food products. Serves also to display, advertise and inform. Alloyed steel (tin can), plastics (thermoplastic polymers),edible coating and films (polysaccharides or protein). Tamper resistance prevents opening before purchase. Pouring feature for convenience. Susceptor (absorbs microwave energy and converts it to heat may be re-emitted as infrared radiation. Susceptor based packaging allow browning reaction in microwave.
Control related operations
Process control is a unit itself. Control valves/pumps, etc. Ensure proper temperatures are reached for proper amount of time, proper fill levels and weights into containers. pH, weight, rate of flow are monitered on control charts.
Control and monitor a control chart, used in control related operations
Control chart: Relies on statistics as materials have random variation due to inherent variability and inherent noise. Important quality assurance tool. Zone C (centerline, + - 1sd), zone b (+-2sd), zone a (+- 3sd), LCL (-3sd), UCL (+3sd). 68percent in C, 95 in c and b, 99,7 in c,b,a. X values are plotted in and everything is under statistical control except if: one point exceeds UCL-LCL, 2 out of thee consecutive point are in zone A, four out of five consecutive are in b or a zone, 8 consecutive points are on one side of central line
System used for quality assurance
Hazard Analysis and Critical Control points (HACCP) system is the most important quality assurance system. Focuses on food safety and utilizes a preventive approach throughout production. All types of hazards are addressed by HACCP : biological, physical, chemical. Mandatory in Canada for meat and poultry also there for other sectors.
Principle 1 of HACCP
Hazard analysis. Identify all possible food safety hazards + measures that can be taken. Ex: at the cooking step, hazard is survival of pathogens due to inadequate cooking time or temp.
Principle 2 of HACCP
Identifying critical control points. Points where actions can be taken to prevent, eliminate or reduce a hazard. Ex: cooking step is a critical control point because control measures are necessary to deal with the hazard of the pathogens surviving the cooking process. If there are more than one in a process, the last one is the critical control point.
Principle 3 of HACCP
Establishing critical limits for each critical point. It is the limit at which a hazard is acceptable without compromising food safety. Ex: critical limits at the cooking stage include specific time and temperature for cooking the product.
Principle 4 of HACCP
Establishing monitoring procedures for critical control points. Ex: taking the internal temperature of the product with a specialized thermometer.
Principle 5 of HACCP
Crucial because establishing corrective actions. Occurs if monitoring indicates deviation from critical limits. Correcting problems before end-stage production is far more effective than waiting before the product is finished to test it. Corrective action would be to cook further if internal temp is not reached, or to hold it and destroy it.
Principle 6 of HACCP
Establishing verification procedures. Applying methods, procedures, tests, sampling and other evaluation to determine if measure at critical control point has been operating as intended.
Principle 7 of HACCP
Record keeping. Used to demonstrate effective application of critical control points + assist official verification (CFIA) + monitoring and verification results + info and actions taken in response to deviation. Cooking log sheet must be filled with date, start and finish time, temperature and employee signature, details of the deviation (if occured)
HACCP and other systems for quality
Industry’s responsibility (not government). Other quality management systems are used in other manufacturing sectors to improve quality. Quality management systems standards developed by international standards organization (ISO) are adopted by many companies in order to obtain ISO certification.
Trade standards
Trade standard and government standards help trade. Trade standards are formulated by both industry associations and governments for most foods, except for meat, poultry, fruits and vegetables that have set grading by CFIA and USDA. Ex: more marbling = better quality = Canada prime. Grade standards are however product-specific and provide producers, consumers, etc a utility guide.
