Meat Packaging– Product Requirements

1. fresh --- uncured, uncooked, not frozena. distribution

– good oxygen barrier

– good water barrier

– sealable

– thermoforms (heat shrink) to reduce purge and adjust to size

– puncture, tear resistant

– EVA/PVDC/EVA -- typical

b. retail

– highly oxygen permeable…or impermeable with CO, NO

– good water barrier

– sealable

– clear, glossy

– tamper, handling resistant

– PVC typical

– unique idea is Cryovac’s peelable

– nitrite-containing film (very low nitrite, no “cure”)

– oxygen and water barrier, high vacuum, “fresh”

product

NOTE: any oxygen-free packaging of fresh meat will

increase shelf life by 5X (from 7 days to 35 days or more)

2. fresh, cooked-packaged after cooked, slicing

– good barrier for both oxygen and water --- some may include aluminum foil and may include oxygen absorbers --- to prevent WOF and rancid flavors

– nylon/PVDC/nylon/EVA typical

“Cook-in” films– good barrier as above

– adhesion properties for product surface to prevent cook purge

– Surlyn ionomers typical

3. fresh, frozen (i.e. poultry)

– good oxygen barrier, medium water barrier at freezer temperature

– shrinkable (prevent frost-recrystallization)

– PE is typical

4. cured, cooked

– good barrier to oxygen and water

– sealable and resealable

– thermoformable

– puncture, tear, tamper resistant

– clear, glossy

– nylon/PVDC/PE typical

Packaging films

– suppliers must provide user with a “Letter of Guaranty” which shows that the film complies with FDA and USDA requirements for end use. An upper limit of temperature is included to insure no migration of film components to product.– this is a current limitation for irradiation processing.

FDA approves packaging films and only Cryovac’s ethyl vinyl acetate (EVA) is approved for e-beam processing

– films may be obtained as bags, pouches, roll stock, etc., virtually all are “laminates” or “coextrusions” and combinations of the basic film types

– permeability is measured (methods by ASTM)

– for gases (usually oxygen)cc/sq m/24 hrs at 1 atm, 23oC, 0% RH

– for water vaporg/sq m/24 hrs at 1 atm, 38oC, 100% RH

– typical levels would be– fresh meat (retail) - 5000 cc

– distribution (vacuum) - less than 30-40 cc

– cooked or cooked, cured– less than 10-15 cc

– also measure

– mechanical strength1. tensile strength

2. puncture resistance

3. elongation (stretching)

– optical properties– clarity (haze) and gloss

– use devices with 45 degree angle (specular angle)

Barrier properties also important to modified atmosphere (MAP) systems

– carbon dioxide (vacuum packed fresh meat is actually a carbon dioxide atmosphere) , nitrogen, oxygen, carbon monoxide

Other factors to consider for barrier properties

1. film thickness– most are 1-4 mil (0.001 inch) thick

– gauge = 1/100 mil (50 gauge = 0.5 mil)

2. temperature– permeability increases as temperature increases

3. relative humidity

– 100% for package containing fresh meat