FSC 211 Exam 2

listeria monocytogenes

concern for people with compromised immune systems, can grow at refrigerator temps, can live in drains, cracks/crevices and in processing plants. good sanitation/cleaning practices are critical

sensory analysis

conducted by using humans as measuring instruments and its important because only humans can determine if a product is good or bad. a statistical analysis of data is usually collected it can be conducted using person/individual sampling/consumer panel, a focus group, or expert taste panel

discriminative tests

conducted to determine if there is a difference among samples that exists. it can be used in quality control applications and when changes have been made to ingredients, packaging, or storage conditions. sometimes it is hoped that no differences can be detected. cant determine the degree that products differ in

food quality

conformance to specifications, conformance to expectations and need

forced air

coveys heat to food and transports the liberated moisture vapor from the dehydrated food. Hot air dryers like cabinets, tunnels, fluidized beds, and sprays are commonly used. important to keep air temp, velocity, and humidity under control tunnels: fruits and veggies, pasta, cereals

commercial sterilization

destruction of all pathogens and nearly all normal spoilage microbes, it is a commonly used method

ergotism

ergot grows and produces ergotism. grows on improperly stored grains through temp and humidity. the toxin survives baking. causes convulsions and gangrene

concentrations and drying

evaporation/concentration like soups, juices, tomato products and dehydration of grains, fruits, vegetables, and spices

forming and sheeting

fabrication of product (size, shape, style, weight, and density), baked goods, breakfast cereals, snack items (sweet and savory products) "complexity increases the need for precision controls)

factors affecting microbial growth

food (provides nutrients, certain microbes prefer certain nutrients moisture: most microbes are inhibited at the water activity below 0.6 pH: most microbes are inhibited at pH below 4.6 temperature: keeping hot things hot and cold things cold time

conditions that lead to food borne illness

food contaminated with pathogen, food in condition favorable to pathogen growth, food consumed in sufficient quantity to get sick. common elements are poor hygiene, poor sanitation, improper cooking, storage temp, or control, or cross contamination

storage time

foods deteriorate over time and growth of microorganisms can occur, destruction by insects or other pests on dry foods, action of food enzymes that contribute to spoilage of food, and loss of flavor volatiles

e.coli

found in the GI tract or feces, or foods contaminated by feces. can be fatal. found in meat (ground), dairy products, unprocessed fruit and vegetable products, that have been contaminated with animal feces. the control is to avoid fecal contamination, have carcass treatments for meat products, and to have thorough cooking of meat products

cleaning and separation:

fruits and vegetables, wash, separate by size, peels. grains and nuts

maillard browning

glucose + amino acid + heat or other reducing sugar. causes a brown color that develops during dehydration of milk, or heating of some foods. examples include milk, dried eggs, and dried potatoes

sun drying

good for taking grapes to raisins and beef to jerky. its a slower method which leaves an increased opportunity for contamination and vitamin loss

enzymatic browning

happens in apples, peaches, pears, avocados, and potatoes and produces melanin

materials and handling

harvest of raw ingredients, transportation to processing facility, conveying of ingredients within facility

drum drying

hollow steel drums slowly rotate and are heated internally by a pressurized stem, water evaporates, solids are scraped off as a film or flakes and the rolls revolve. can dry highly sticky products like oatmeal, mashed potatoes, or fruit leathers

fluidized bed drying

hot air is blown through the bed, causing the food to become suspended and vigorously agitated. limited to small particulate foods that are capable of being fluidized without excessive mechanical damage

descriptive tests

identify sensory characteristics that are important in a product and give information on the degree or intensity of those characteristics yield more product info than discriminative tests identify ingredient or process variables responsible for specific sensory characteristics of a product develop new products improve products or processes, and to provide quality control

spectrophotometer

is used for color measurement of liquids the light of a particular wavelength is passed through a small tube of liquid light is absorbed depending on the color of the liquid and the intensity of the color. ex: a concentrated juice should absorb more light than a more dilute sample

How is thermal processing affected by product characteristics, container size, retort type, etc.?

it can be influenced by product composition and characteristics because it might have a serenity of food to heating and microbes to destruction

salmonella

it is an aerobic/facultative mesophile with a low infectious dose. its most commonly found in poultry and its control needs proper handling and cooking

lipoxygenase

leads to rancidity and off flavors in polyunsaturated vegetable oils like soy oil as well as cause loss of pigments in fish like salmon or trout

affective tests

measures attitudes towards a product based on its sensory properties, and results give an indication of preference, liking, or acceptance of a product

bostwick consistometer

measures consistency of viscous material by measurement of the distance over which the material flows on an inclined plane under tis own weight during a given time interval tomato products, jams, preserves, puddings

kramer shear press and instron

measures properties of firmness, crispness, chewiness, and hardness

adams consistometer:

measures the consistency of foods by the degree of spread or flow of the product in all directions at a given time

quantitative descriptive analysis (QDA)

methods. trained panalists quantify and describe specific product characteristics, products can be compared, characteristics can be optimize

pasteurization

mild heat treatment that provides increased shelf stability and elimination of pathogens. its good for fluid products prior to packaging like milk and juices, good for acid and acidified foods like pickles, sauerkraut, fruits, bottled beer after packaging.

size reduction

milling of grains into flour, cutting/chopping fruits, veggies, and meats, grinding, homogenization of milk

flavor:

the combo of taste, odor, and mouthfeel aroma may account for 75% of impression of flavor tastes: perceptions caused by soluble substances when dissolved by saliva in mouth sensation of flavor can be influenced by chemical feeling factors (trigeminal sensations), astringency, spice heat, cooling gas chromatograph: can be used to separate, quantitate, and identify volatile compounds

Factors to consider in thermal processing

the nature of the product. What is the pH? because the pH of 4.6 is the critical control point, what's the texture? and what are the protective constituents like sugar and lipids that can interfere with heat penetration and require a higher temperature. What microbes are present? What is the size/shape/type of package? larger containers take longer to process bc heat must penetrate the entire product/package. how is heat transferred into the container and throughout the product?

heating

thermal preservation to destroy microbes, sterilization processes, canning, UHT (milk, soup, juices), baking, roasting, milder heat processes like blanching and pasteurization

triangle test

three coded samples: two are alike and one different, which is the odd sample?

d value

time (in minutes) needed to destroy 90% of cells at a given temperature (1 log reduction) specific organisms have a different resistance to heat and therefore have different D values

aflatoxin

toxins produced by aspergillus in peanuts, grains, and its a carcinogen

intrinsic

type/nature/composition of food like pH, aw, constituents (CHO, Lipid, proteins) fruit/veg, meats, cereals or grains or common microbial flora

freeze drying

under defined temp and pressure conditions, water will pass directly from a solid to a vapor without going through the liquid phase (sublimation). no thawing occurs, the low temp maintains conditions for minimum quality changes and the loss of volatile components is kept at a minimum. however, it is expensive

oxygen and air

unsaturated fatty acids, action of polyphenol oxidase, and has destructive effects on nutrients, colors, and flavors

lipid oxidation

unsaturated lipids are susceptible to oxidation and oxidation attacks double bonds and result in off flavors, destruction of some vitamins, and color changes. can happen in old potato chips, old peanut butter, leftover turkey the rate of oxidation increases with the increased degree of unsaturation, increased temp, increased oxygen concentration

light

vitamin degradation, deterioration of color, oxidation of flavors and aromas physical forces: crushing, breakage, loss of product

paired preference

which do you prefer

paired comparison

which one is sweeter? fruiter? saltier? more orange?

hunter L, a, b system

based on the opponent-color (opposite colors) theory of color vision and assigns numeric values to three parameters L (lightness): black or white a: green or red b: blue or yellow

viscometers and consistometers

can be used to measure the flow properties of products. methods may involve an incline plane, rotating spindle, "degree of spread"

How microbes get into/contaminate food

can enter via many vectors like aire, water, soil, animals, or humans. they can grow in or on food. the most common types in food are bacteria, mold, or yeast

staph aureus

can grow in aerobic but facultative, pH of 4.5-10, and comparatively salt tolerant. The toxin is what causes the illness and it can't be destroyed by cooking. so prevention of the organism and production of the toxin need to be controlled.

texture

can influence acceptability of food as much as or even more than aroma/flavor it refers to the rheological properties of a food item and may be perceived through visual appearance

oxidases

catalyze reactions with oxygen, like the enzymatic browning of certain fruits and vegetables through polyphenol oxidase. also the oxidation of unsaturated fats through lipoxygenase

carbohydrase

causes breakdown of CHO in hydrolysis reactions. this is the softening of fruits and vegetables and deterioration of plant foods

Temperature

causes protein denaturation, emulsion breakdown, texture changes moisture: affects rate of chemical reactions and growth of microbes. could cause lumping, caking, and surface defects

Lipase

causes release of fatty acids from the glycerol backbone (hydrolytic rancidity, does not involve oxygen). The lipase enzyme can be released by bacteria, which can occur naturally in milk. can be desirable in aged cheese, but defect in butter and milk

proteases

cleave proteins, can have desirable effects or can cause deterioration in meat tenderization or breakdown of fish and seafood. Bacteria can also produce proteases

unit operations

common operations used in production of foods and several different unit operations may be utilized in making a single food item

enzymatic

complex proteins that act as biological catalysts. temp, pH, and water activity can affect enzymes. they don't work at certain temps, there is an optimum activity range for pH, and as water activity decreases, so does enzyme activity

Whats the gold standard?

Sensory

How is food quality determined?

appearance, aroma, texture, flavor (taste + aroma)

inoculate

a model system with known amount of microbes, heat it at a specific temp for varying times, plot the number of survivors vs. time of heateing, and determine a D value

spray drying:

a spray dryer is a device for drying utilizing a spray, it mixes a heated gas with an atomized liquid stream within a vessel/drying chamber. products include: milk products, infant formula, eggs, juice powders and coffee. advantages are very short drying times, not as damaging to flavor, color, and nutritive value as other air drying systems

12D

amount of time needed to achieve 10^12 reduction in microbes at a given temperature. ex: suppose 1 mil cans each containing 1 mil cells are processed, after 12D only 1 cell remains: 10^12 spores become 1.0 spores

clostridium perfringens

anaerobe mesophile that produces mildly heat resistant spores, found in meat and poultry (only in produce from cross contamination). control spread through proper handling, refrigeration, and reheating of cooked or prepared meats. called thanksgiving day food borne illness or cafeteria germ

processes that affect food dehydration

size/shape, physical structure, physical properties. The drying rate of food increases with a greater surface area and the more porous the surface. the drying rate decreases with high levels of sugar or salt

clostridium botulinum

strict anaerobe, produces a neurotoxin and has high incidence of mortality, doesn't take a lot to get you sick, found in inadequately processed canned or vacuum packaged foods. control growth through adequate thermal process bc the spores are resistant to heat

extrinsic (environmental)

temperature, moisture, oxygen, light, physical forces like transportation and storage, and time

packaging and distribution

package sufficiently to meet requirements and protect the product, during distribution the product must be maintained under controlled conditions.... traceable and accessible for market removal

conventional canning

prepare the product by peeling, trimming, slicing, or cutting. fill and seal the containers and deliver the required thermal treatment using the retort system

aseptic processing

prepare the product, commercially sterilize the product and container separately and fill the sterile container with the product. this can be used for liquids, purees, very small pieces, no additional heat treatment is needed, and it yields commercially sterile products that are shelf stable

dehydration

preservation by lowering the moisture content/water activity, drying does not destroy microbes, decreases the weight and bulk which is beneficial for shipping and storage, good for making instant products like instant oatmeal, coffee, tea, or potatoes

mixing and blending

product formulation (dry ingredients), liquids, air (ice cream), increased interactions among ingredients

pasteruization

provides increased shelf stability and elimination of pathogens

ranking test

rank samples from low to high based on intensity of a specific characteristic

cooling

refrigeration and cold storage, like raw ingredients and finished products or freezing

Color

related to three factors, intensity and wavelength of the illuminating light source, chemical and physical properties of the object, and sensitivity of the "eye of the beholder", perception

Control of deteriorative reaction, oxidation, enzymes

remove/reduce oxygen through use of barrier packaging, back flush with nitrogen, oxygen scavengers reduce the temperature use antioxidants like BHT, Tocopherols (vit E), and herbs like rosemary

brookfield viscometer:

sample is presented in a cup, the spindle submerged and electric motor rotates the spindle in the sample, and the torque resistant force is recorded (more force=higher viscosity) custards, pie fillings, mustards, ketchup, mayo, salad dressings, dairy products

hedonic

scaling tests (5, 7, or 9 point "degree of liking"

mycotoxins

secondary metabolites produced by fungi, the mold produces mycotoxins

aroma/odor

sensation of odor arises from the stimulation of exposed nerve endings in the nasal cavity by volatile gaseous compounds highly complex blends of volatile compounds (aldehydes, ketones, phenols) slight difference in molecular structure can result in vastly different aromas/odors the aroma of an odorous substance is influenced by its chemical and molecular structure

safety concerns associated with dehydration

you want to prevent the uptake of oxygen and moisture, the flavor contamination, mechanical and physical damage, contamination by insects and microorganisms, and exposure to light. the seal integrity of the package is also critical