24.1 Meat, Poultry, Fish, Eggs, and Milk: Structure, Quality, Storage, and Cookery
Key Takeaways
Tender meat cuts with little connective tissue suit dry-heat cooking, while less tender cuts need slow, moist heat that converts collagen to gelatin.
Myoglobin is purple-red, oxymyoglobin is bright red, and metmyoglobin is brown, while cured meats are pink from nitrosyl pigments.
Fresh fish have bright, bulging eyes, red gills, firm elastic flesh, and a mild sea odor.
A fresh egg sinks and lies flat in water because its air cell is small, while an old egg floats as the air cell enlarges.
Milk scum forms from coagulated casein and calcium at the surface, while curdling is caused by acid, tannins, salt, enzymes, or high heat.
The Understanding Foods competency area covers the composition, classification, market forms, preparation, and storage of animal foods. Protein denaturation, connective tissue changes, and the green ring in boiled eggs are explained in the food chemistry section.
Meat
Structure: muscle fibers bundled by connective tissue (collagen, which softens to gelatin with moist heat, and elastin, which does not soften), with fat around and within muscle (marbling).
Post-slaughter changes: rigor mortis stiffens muscle as ATP is used up; aging (holding chilled meat) lets natural enzymes tenderize it.
Color:
| Pigment | Color | When |
|---|---|---|
| Myoglobin | Purple-red | Freshly cut or vacuum-packed meat |
| Oxymyoglobin | Bright red | Exposed to oxygen |
| Metmyoglobin | Brown | Prolonged storage or oxidation |
| Nitrosyl pigments | Pink | Cured meats such as ham, tocino, and longganisa with curing salts |
Tenderness factors: amount of connective tissue (cuts from heavily used muscles like shank and brisket are tougher), animal age, marbling, aging, and cooking method. Tenderizers include papain from papaya, bromelain from pineapple, marinating in acid, pounding, and cutting across the grain.
| Cut type | Examples | Cooking method |
|---|---|---|
| Tender | Loin, tenderloin, rib | Dry heat: grill, roast, pan-fry |
| Less tender | Shank, brisket, chuck, oxtail | Moist heat: braise, stew, simmer (as in bulalo and kare-kare) |
Safe minimum internal temperatures (USDA consumer guidance): whole cuts of beef and pork 63 °C with a 3-minute rest; ground meat 71 °C; poultry 74 °C; reheated leftovers 74 °C. Food service HACCP plans often use the FDA Food Code time-and-temperature combinations described in the HACCP section.
Inspection: the National Meat Inspection Service under the Department of Agriculture enforces the Meat Inspection Code (RA 9296). Buy meat with inspection marks from accredited sources.
Poultry
- Classes: broiler or fryer (young, tender), roaster, and stewing hen (older, tougher, best for soups).
- Light meat (breast) has less myoglobin and fat than dark meat (legs and thighs).
- Poultry often carries Salmonella and Campylobacter, so prevent cross-contamination and cook thoroughly.
Fish and Shellfish
- Fin fish: lean (lapu-lapu, tilapia) or fatty (bangus, galunggong, tuna, sardines).
- Shellfish: crustaceans (shrimp, crab, lobster) and mollusks (clams, mussels, oysters, squid).
- Freshness signs: bright, clear, bulging eyes; red gills; firm flesh that springs back; shiny skin with tight scales; mild sea odor.
- Fish has little connective tissue, so it cooks quickly; overcooking makes it dry.
- Hazards: histamine (scombroid) poisoning from improperly chilled tuna and mackerel; paralytic shellfish poisoning from red tide toxins, which cooking does not destroy (follow BFAR shellfish bulletins); parasites in raw fish.
Eggs
Structure: porous shell, shell membranes, air cell at the broad end, thick and thin white, chalazae holding the yolk, and the yolk.
Functions in cookery:
| Function | Example |
|---|---|
| Emulsifying (lecithin in yolk) | Mayonnaise |
| Foaming and leavening | Meringue, sponge cake, chiffon |
| Binding | Meatloaf, embutido |
| Thickening | Custards, leche flan |
| Coating | Breaded fish |
| Clarifying | Consommé |
Freshness: as eggs age, the air cell enlarges, the white thins, and the yolk flattens. In water, a fresh egg sinks and lies flat, an older egg tilts or stands, and a stale egg floats. Candling shows the air cell and defects.
Egg white foams: stages are foamy, soft peaks, stiff peaks, and dry (overbeaten). Cream of tartar (acid) stabilizes foams; sugar stabilizes but delays foaming, so add it gradually; any yolk or fat prevents foaming; whites at room temperature whip faster.
Storage: refrigerate, broad end up, away from strong odors; do not wash before storage because washing removes the protective cuticle.
Milk
Composition of cow's milk (approximate): water 87%, lactose about 4.8%, fat about 3.5-4%, protein about 3.3% (about 80% casein and 20% whey), plus calcium, riboflavin, and vitamin A. Carabao milk is richer in fat.
Processing:
- Pasteurization: low-temperature long-time (63 °C for 30 minutes) or high-temperature short-time (72 °C for 15 seconds) destroys pathogens.
- Ultra-high temperature (UHT): about 135-150 °C for a few seconds, packed aseptically for shelf-stable milk.
- Homogenization: breaks fat globules so cream does not separate.
- Fortification with vitamins A and D.
Market forms: fresh, UHT, evaporated (about 60% of water removed), sweetened condensed (concentrated with added sugar), powdered, filled milk (milk fat replaced with vegetable oil), yogurt, and cheese such as kesong puti from carabao milk.
Milk cookery problems:
| Problem | Cause | Prevention |
|---|---|---|
| Scum (skin) | Casein and calcium coagulate at the surface as water evaporates | Cover the pan, stir, or whip to form foam |
| Scorching | Proteins and lactose stick and burn on the bottom | Low heat, double boiler, constant stirring |
| Curdling | Acid (tomatoes), tannins (fruits, tea), salt, enzymes, or high heat | Thicken milk or the acid food with starch first, add acid to milk slowly, use low heat |
| Boiling over | Foam traps steam | Moderate heat; watch closely |
Storage: refrigerate fresh milk at 5 °C or below; keep UHT milk cool until opened, then refrigerate.
Which cooking method is best for beef shank in bulalo?
Quick grilling over high heat for a smoky crust
Stir-frying for 3-5 minutes
Slow simmering in liquid for several hours
Broiling until medium-rare
During receiving, which sign indicates that fish are fresh?
Bright, bulging eyes and red gills
Sunken, cloudy eyes and gray gills
Soft flesh that keeps a finger dent
A strong ammonia odor
A cook pours cold milk into hot tomato soup and the milk curdles. Which change best prevents curdling?
Boil the soup rapidly after adding the milk
Add salt to the milk before mixing
Use more tomatoes for a stronger acid flavor that stabilizes the milk proteins
Thicken the milk with starch and add the tomato gradually at low heat
Sections you finish are checked off in the contents.