Preservation technique of meat

1. Unit IV- Processing & preservation of meat
Meat aging
Meat, poultry and fish Processing technology
B. Tech. Final Year / Sem 7 (2021-22)
Mrs. Snehal P. Khandekar

2. Meat Aging (Conditioning / Ripening )
• Ageing is considered as very important aspect of meat processing as it
imparts desirable flavours, textural and other sensory attributes to the
finished product.

3. Mrs. S. P. Khandekar
• Fresh unpackaged carcass and meat can be stored providing it remains
wholesome, as indicated by the absence of dryness, discoloration, visible
mold growth, sliminess or odor.
• Meat stored for ageing purposes must be subjected to a controlled,
documented and approved ageing procedure.
• Ageing is the process during which microbes and enzymes act upon the
meat to help breakdown the connective tissue to tenderize the meat. There
are two ways ageing can be accomplished:
• Wet ageing by placing beef in a plastic bag under vacuum; or
• Dry ageing by storing beef in a temperature and humidity controlled
environment (room/chamber)
• The main difference is that wet ageing results in little or no moisture loss,
whereas dry ageing can result in up to 50% moisture loss. Product labelling
should indicate the ageing processes used.

4. Mrs. S. P. Khandekar
1. Dry ageing storage conditions:
• Temperature: between - 0.5°C to 1°C (2°C to 3°C may be used when only
ageing for up to 3 weeks);
• Relative Humidity: between 75% to 85%;
• Air velocity: between 0.2 to 0.5 m/s.
2. Wet ageing storage conditions:
• Storage below 5°C;
• Validation testing than any mold is Thamnidium;
• Shelf life testing for Enterobacteriaceae and E.coli at the end of the
ageing period.

6. Factors & Changes during Ageing
1. Flavor
• Dry ageing involves the degradation of connective tissue and muscle protein
structure of the meat of carcasses or cuts of meat and must be managed to ensure
growth of beneficial and non-harmful molds.
• Best practice is to reduce carcasses to smaller primals and sub-primals in
preparation for the ageing process.
• Dry aged beef has an intense flavour when compared to wet aged meat that can
have a sour blood/serum flavour.
• The reason for this is that the predominant bacteria on dry aged meat are the
Pseudomonas that grow in the presence of oxygen.
• This is different to wet aged packaged meat where Lactobacilli bacteria grow in
the absence of oxygen.
• The Lactobacilli bacteria convert lactose to lactic acid therefore wet aged product
may have a slightly sour taste or odor when compared to the Pseudomonas that
do not produce any sour flavours on dry aged meat.

7. • The flavor of dry aged beef can range from buttery to nutty.
• The flavor is also dependent on other factors such as the quality of the meat
cut, storage temperature and relative humidity during ageing.
• Premium products can be dry aged for up to 6 weeks.
• It may be difficult to maintain the wholesomeness of meat after 8 weeks of
dry ageing.

8. 2. Enzymatic action
• Endogenous proteolytic enzymes from the meat itself as well as from the
specific beneficial molds weaken the structural Myofibrillar proteins in the
meat.
• This takes 10 to 14 days and results in a more tender meat.
• At this stage the meat flavours can usually be described as buttery and
smooth.
3. Evaporation
• Loss of water from the meat by evaporation causes increase in concentration
of the proteins and increases flavour intensity to a nutty taste.
• Final water loss can be up to 50% and depends on the relative humidity used
during drying.

9. 4. Relative humidity
• If the humidity is too high, it will result in the growth of spoilage
bacteria, which would produce an off-flavor.
• If the humidity is too low, bacteria growth will be limited but
evaporative weight loss will increase causing the meat to dry out
quickly, resulting in a decrease in juiciness.
• The preferred range of relative humidity is 61%–85% and should be
recorded and checked daily to maintain control.

10. 5. Tenderness
• Dry aging promotes the growth of beneficial mold on the
surface of the meat like Thamnidium.
• It has the appearance of a pale gray color and will form
patches, called whiskers, on the fatty parts of the carcass or
cut.
• Thamnidium’s enzymes are able to break down muscle and
connective tissues by penetrating into the meat and emitting
proteases and producing collagenolytic enzymes.
• Proper handling practices, aging time, temperature, relative
humidity, and airflow are required to grow beneficial mold and
limit other microbial contamination.

11. 6. Airflow
• It is crucial to have sufficient airflow in the refrigerated room to have
adequate air circulation.
• The meat will not be able to release the required amount of moisture for the
drying process without sufficient air circulation.
• However, if there is too much circulation, the meat could dry out too
quickly.
• The recommended range of airflow is 0.5–2 m/s (1.6–6.6 ft/s) with a
velocity of 0.2–1.6 m/s.
• It is important that airflow and velocity stay consistent through the entire
dry aging process.

12. 7.Antibacterial Strategies
• The use of ultraviolet (UV) light for destruction of bacterial cells is
well known for fresh meat.
• A more sophisticated approach to manage the dry ageing process is to
install UV lighting entirely and leaving no other light source.
• Air can also be circulated through UV light chambers.

13. Testing wholesomeness of Aged Meat
• The quality and wholesomeness of meat for human consumption can be
determined by basic observations of dryness, discoloration, visible mold growth,
sliminess and odor.
• Meat processing facilities are required to comply with the requirements
of Australian Standard for the Hygienic Production and Transportation of Meat
and Meat Products for Human Consumption (AS 4696:2007) with regards to the
management of wholesomeness.
• The dry ageing of beef can be for up to eight weeks, depending on the product
characteristics required.
• Dry aged meat products must be tested for mold to validate the procedure.
• Growth of Thamnidium mold can start from three weeks after commencing the
ageing process.
• Testing involves removing a 100g portion of untrimmed aged meat that includes
visible mold if it is present, and sending it for testing at laboratory.

14. • If testing for mold shows that the results are positive, then confirmation
that the mold is Thamnidium must be conducted.
• For wet aged meat products there will be no growth of mold due to the
lack of oxygen in the bag therefore there is only a requirement to confirm
the wholesomeness of the product.
• To confirm the wholesomeness of dry and wet aged products, the shelf life
must be validated by testing for Enterobacteriaceae and E.coli.
• The critical limits for wholesomeness for these purposes are
microbiological limits of Enterobacteriaceae of 1,000cfu/g and E.coli of
10cfu/g.
• Five 10 gram samples must be taken for testing of both Enterobacteriaceae
and E.coli.

15. Testing Flow Chart

16. Thank You !!!