Other Conditions

There are several conditions in food products that may be confused with deterioration but present no potential health hazard.

a. Struvite Crystals. Small crystals of a harmless chemical substance, magnesium ammonium phosphate (also referred to as struvite), often gradually form in fish and shellfish packs. The constituents of these crystals are necessary for normal health. They cause no harm if swallowed. However, the crystals are often mistaken for glass and thus are undesirable. Their formation may be reduced or eliminated by the addition of certain chemicals to waterfoods prior to canning. Struvite crystals are commonly seen in cans of tuna and salmon.

PERISHABLES

MODE OF DETERIORATION (Assuming an Intact Package)

CRITICAL ENVIRONMENTAL FACTORS

Fluid milk and dairy products

Bacterial growth, oxidized flavor, hydrolytic rancidity

Oxygen, temperature

Cheese

Rancidity, browning, lactose crystallization, undesirable mold growth

Temperature, relative humidity

Ice cream

Graininess cause by ice or lactose crystallization, texture

Fluctuating temperature (below freezing)

Fresh red meat

Bacterial growth, loss of red color

Oxygen, temperature, light

Fresh poultry

Bacterial growth, off-odor

Oxygen, temperature, light

Fresh fish

Bacterial growth, off-odor

Temperature

Fresh fruits and vegetables

Respiration, compositional changes, nutrient loss, wilting, bruising, microbial growth

Temperature, relative humidity, light, oxygen, physical handling

Frozen meats, poultry, fish

Rancidity, protein denaturation, color change, desiccation (freezer burn), toughening

Oxygen, temperature, temperature fluctuations

Frozen fruits and vegetables

Loss of nutrients, loss of texture, flavor, odor, color, and formation of package ice

Oxygen, temperature, temperature fluctuations

Frozen concentrated juices

Loss of cloudiness, yeast growth, loss of vitamins, loss of color or flavor

Oxygen, temperature, temperature fluctuations

Frozen convenience foods

Rancidity in meat portions, weeping and curding of sauces, loss of flavor, loss of color, package ice

Oxygen, temperature, temperature fluctuations

Figure 1-1. Major modes of deterioration, perishables.

SEMIPERISHABLES

MODE OF DETERIORATION (Assuming an Intact Package)

CRITICAL ENVIRONMENTAL FACTORS

Fresh bakery products

Staling, microbial growth, moisture loss causing hardening, oxidative rancidity

Oxygen, temperature, humidity

Breakfast cereals

Rancidity, loss of crispness, nutrient loss, breakage

Relative humidity, temperature, rough handling

Pasta

Texture changes, staling, vitamin, and protein quality loss, breakage

Relative humidity, temperature, light, oxygen, rough handling

Fried snack foods

Rancidity, loss of crispness, breakage

Oxygen, light, temperature, relative humidity, physical handling

Dehydrated foods

Browning, rancidity, loss of color, loss of texture, loss of nutrients

Relative humidity, temperature, light, oxygen

Nonfat dry milk

Flavor deterioration, loss of solubilization, caking, nutrient loss

Relative humidity, temperature

Coffee

Rancidity. loss of flavor and odor

Oxygen, temperature, lights, relative humidity

Tea

Loss of flavor, absorption of foreign odors

Oxygen, temperature, light, humidity

Canned fruits and vegetables

Loss of flavor, texture, color, and nutrients

Temperatures

Figure 1-2. Major modes of deterioration, semiperishables.

Figure 1-2. Major modes of deterioration, semiperishables.

b. Tartrate (Argol) Crystals. These crystals precipitate (clump together) readily from grape juice in storage. These crystals, commonly called argol, are not harmful, but are often mistaken for glass. Thus, the crystals are undesirable. The crystals are normally removed during the normal processing procedures by filtering.

c. Tyrosine Deposits. Tyrosine occasionally forms a whitish deposit on many foods, chiefly noted on Swiss cheese. However, it also forms on herring and anchovy packs, bacon, ham, and sausages. This amino acid, due to its low solubility, precipitates when migrating to the surface.

(1) In Swiss cheese, tyrosine crystals appear in the holes. Their occurrence is due to certain conditions in the manufacture of the cheese.

(2) In the case of canned herring, the whitish patches appear only in the bottom of the can, since the brine must be in free contact with the fish surface.

(3) Lengthy storage is necessary for this change to occur in bacon and dry sausages (salami and pepperoni), although the exact conditions have not yet been established.

d. Calcium Lactate Deposits. White specks occurring on any type of matured cheese have been identified as calcium lactate, with or without tyrosine crystals. The whitish deposits are easily observable in rindless cheeses. The rind of conventional cheese evidently masks the visual signs of this crystallization. Cheese in flexible packages is more prone to surface crystallization. Any excessive handling or moisture losses initiate crystal formation.

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