food packaging preservatives materials

1. Presented by:
Darshan Gohel
B.Tech Agricultural
Semester 7
U42000001415

2. Overview
 Food preservatives can be extrinsic (intentionally added), intrinsic (normal
constituent of food), or developed (produced during fermentation). Factors
affecting preservative effectiveness include:
(1) concentration of inhibitor
(2) kind, number, and age of microorganisms (older cells more resistant)
(3) temperature
(4) time of exposure (if long enough. some microbes can adapt and
overcome inhibition)
(5) chemical and physical characteristics of food (water activity, pH,
solutes, etc.).
 Preservatives that are cidal are able to kill microorganisms when large
concentrations of the substances are used. Static activity results when
sublethal concentrations inhibit microbial growth.

3. Types of preservative releasers
 Organic acid
 Silver zeolite
 Spice and herbs extracts
 BHA/BHT antioxidants

4. Organic acids
 Organic acids are used in food preservation because of their effects on
bacteria. The key basic principle on the mode of action of organic acids on
bacteria is that non-dissociated (non-ionized) organic acids can penetrate
the bacteria cell wall and disrupt the normal physiology of certain types of
bacteria that we call pH-sensitive, meaning that they cannot tolerate a wide
internal and external pH gradient. Among those bacteria are Escherichia
coli, Salmonella spp., C. perfringens, Listeria monocytogenes,
and Campylobacter species.
 It has been well demonstrated that the state of the organic acids
(undissociated or dissociated) is extremely important to define their
capacity to inhibit the growth of bacteria, compared to undissociated acids.
 Organic acids have been used successfully in pig production for more than
25 years and in poultry production

5.  A few common examples include:
o Lactic Acid
o Acetic Acid
o Formic Acid
o Citric Acid
o Oxalic Acid
o Uric Acid
o Malic Acid
o Tartaric Acid

6. Silver zeolite
 The properties of the bactericidal action of silver zeolite as affected by
inorganic salts and ion chelators were similar to those of silver nitrate. The
results suggest that the contact of the bacterial cell with silver zeolite, the
consequent transfer of silver ion to the cell, and the generation of reactive
oxygen species in the cell are involved in the bactericidal activity of silver
zeolite.

7.  The shelf life of the meat will usually be 2 or 3 days in refrigeration environment. To
improve the meat’s shelf life, properties of packing material should be improved.
One of the packing materials of meat isBi-axial Oriented Poly Propylene (BOPP)
film. Usually, the aluminium coating will be done on BOPP film which improves the
thermal resistance and barrier properties of the packaging films like oxygen
transmission rate, water vapour transmission rate etc.The bacterias which majorly
reduces the quality of the meat are
(1)Listeria monocytogenes,
(2) Clostridium perfringens,
(3) Salmonella,
(4) E coli 0157 and
(5) Campylobacter.

8.  Alternatively, the Silver and Zinc- containing Zeolite (SZZ) coating act as
antimicrobial agent for all five mentioned bacterias. Therefore, SZZ coating is
deposited on the BOPP film using vapour deposition method. Consequently, the SZZ
coating inhibit the colony forming units when compared to uncoated films surfaces.
Further, SZZ coating improves the molecular bonding between the aluminium and
SZZagents. Hence, in this research work, SZZ coating was deposited on the BOPP
film and its effect of microbial activity is evaluated. It was found that after 4 hours
exposure in agar test, microbial activity had been reduced upto 92.67 percent and
after 24 hours of exposure, the microbial activity further reduced upto 98.5 percent.

9. Spice and herbs extracts
 The antibacterial efficiency of five spice and herb extracts (cinnamon stick,
oregano, clove, pomegranate peel, and grape seed) against Listeria
monocytogenes, Staphylococcus aureus, and Salmonella enterica in cheese
at room temperature (~ 23°C). The lipid oxidation (thiobarbituric acid-
reactive substances) of cheese was periodically tested by oxidative analyses.
The results showed that all five plant extracts were effective against three
foodborne pathogens in cheese. Treatments with these extracts increased the
stability of cheese against lipid oxidation. Clove showed the highest
antibacterial and antioxidant activity. The reduction of foodborne pathogen
numbers and the inhibition of lipid oxidation in cheese indicated that the
extracts of these plants (especially clove) have potential as natural food
preservatives.

10. BHA/BHT antioxidants
 Butylated hydroxyanisole (BHA) and the related compound butylated
hydroxytoluene (BHT) are phenolic compounds that are often added to
foods to preserve fats and oils and keep them from becoming rancid. They
are added to food, cosmetics, and packing of products that contain fats to
maintain nutrient levels, color, flavor, and odor. BHT is also sold as a
dietary supplement for use as an antioxidant. The chemicals are found in an
extensive list of products, yet there is concern about their safety. Take a
look at the chemical properties of these molecules, how they work, and why
their use is controversial.

11. • BHA is generally used to keep fats from becoming rancid. It is also used as a
yeast de-foaming agent. BHA is found in butter, meats, cereals, chewing gum,
baked goods, snack foods, dehydrated potatoes, and beer. It is also found in
animal feed, food packaging, cosmetics, rubber products, and petroleum
products.
• BHT also prevents oxidative rancidity of fats. It is used to preserve food odor,
color, and flavor. Many packaging materials incorporate BHT. It is also added
directly to shortening, cereals, and other foods containing fats and oils.