Copy of MEAT SPOILAGE

MEAT SPOILAGE:

A CRITICAL REVIEW
OF A NEGLECTED

ALTERATION DUE TO
ROPY SLIME

PRODUCING BACTERIA

MIC 500
(FOOD MICROBIOLOGY)

AS2463C
GROUP 11
PREPARED FOR:
DR KHALILAH BT ABDUL KHALIL

CONTENTS

1 about us 2 introduction

factors factors

3 influencing shelf- 4 influencing shelf-
life
life
intrinsic factors
extrinsic factors
factors
alteration
5 influencing
6 associated with
spoilage of meat
spoilage

filaments and lactic acid bacteria

7 ropy-slime 8 associated with

meat spoilage

9-10 prevention 11 conclusion

12 references

I

ABOUT US

Muhammad Firdaus
Nasran Bin Md Sairy

2020455592

Nur Sharmira Binti Sahar
2020822534

Nurul Athierah Binti Abd
Karim

2020449348

Intan Suraya Binti Mhd
Khoir

2020822348

1

INTRODUCTION

Food rejection is mainly
associated with spoilage

Meat represents one of the
most perishable food

Ropy slime - alteration of
the surface of vacuum and
MAP cooked meat products

·This determines huge
financial losses for food

producers.

2

EXTRINSIC FACTORS

FACTOR INFLUENCING SHELF-LIFE

INTRINSIC FACTORS

INTRINSIC FACTORS

COMPOSITION AND WATER ACTIVITY
ANTIMICROBIAL HURDLES
Antimicrobial agents are added Water activity (aw) is the
measure of the amount of
to prevent bacterial
contamination of food. water in a food.
The addition of bioprotective Dried products are usually

cultures and natural considered shelf stable.
antimicrobial compounds to Control of the drying process

meat products. to prevent the growth and
Shows remarkable antimicrobial toxin production of
pathogens.
activity against spoilage and
pathogenic microorganisms in 3

meat and meat products.

EXTRINSIC FACTORS

STORAGE TEMPERATURE PACKAGING AND GASEOUS
Storage temperature affects the ATMOSPHERE

duration of the lag phase Packaging of meat under
Lower refrigeration. vacuum or CO2 modified

temperatures decrease bacterial atmosphere
growth and modify the The use of CO2 and N2
extends the lag phase
composition of the microbiota. ·Modified atmosphere
packaging (MAP) meats are
affected by dynamics
changes of headspace gases.

4

FACTOR INFLUENCING SPOILAGE OF MEAT

STORAGE TEMPERATURE PACKAGING AND GASEOUS
Temperature abuse determines ATMOSPHERE

the growth bacteria. Aerobic storage conditions.
Temperature abuse occurs Lactic acid bacteria are the
when the product is allowed to predominant microflora of
remain a sufficient length of vacuum or CO2-modified
time at temperatures favorable
atmosphere packed
to pathogen growth. products.

5

ALTERATIONS ASSOCIATED WITH SPOILAGE

OFF ODOURS AND FLAVOURS
Sour , acid aroma caused by lactic
acid bacteria that produce lactic and
acetic acid during the logarithmatic

and stationary growth phase.

COLOUR ALTERATION
Leuconostoc spp. and Leuconostoc-

like microorganisms, such as
Weissella viridescens, may cause
meat products to turn green, due to
the formation of hydrogen peroxide.

GAS PRODUCTION
Clostridium spp. is responsible for the
production of a large amount of gases

(H2 and CO2).
Vacuum-packed meat could be
affected by blown pack spoilage

FILAMENTS AND ROPY SLIME
A high incidence of ropy slime
formation is found in vacuum-
packed, cooked meat products.

6

FILAMENTS AND ROPY
SLIME

Stretchy, long, undesirable
polysaccharides ropes

between the surface of the
products and the casing or

between the slices.
A protective layer to keep

bacteria moist.

Homofermentative
Lactobacillus spp and
Leuconostoc spp. found in
vacuum-packed cooked

meat products.
W. viridescens produces ropy

slime/turning meat green

7

SEPTEMBER 2020, ISSUE 1 THE VOICE
Lactic acid bacteria associated with
meat spoilage

Causes sensory changes, such as souring, the
production of H2S, gas and slime.
Ropy slime-producing lactobacilli belong to the
atypical streptobacteria i.e., heterofermentative
psychrotrophic lactobacilli.
Atypical streptobacteria are characterized by
their ability to grow at a lower temperature (2-
4°C) than other streptobacteria.

Timelapse of beef steak
rotten

This low, minimum growth temperature allows these bacteria
to survive and compete with other bacteria in meat products
and meat processing plants.
The use of low temperatures in the preparation and storage
of meat products does not prevent the formation of ropy-
slime, although refrigeration storage temperature determines
a longer shelf-life of the product.
The optimum temperature of growth is 30°C and such high
temperatures are not usually reached during the storage of
meat products, in spite of temperature abuses.

8

PREVENTION

1. USE OF DETERGENTS AND SANITIZERS

The rooms and equipment of meat
processing plants act as sources of
bacterial contamination and
disinfection is a necessary procedure
to minimize contamination.
Temporal and spatial separation
between raw meat and cooked
products decreases the risk of cross-
contamination.
Detergents contain surfactants that
reduce surface tensions between the
soil and the surface while sanitizers
are made of antimicrobial
compounds able to reduce the
microbiological contamination to an
acceptable level, according to local
health regulations.
In meat processing plants, it is better
to use separately detergent and
sanitizers than use combined
detergents and sanitizers products.
Quaternary ammonium products and
acid sanitizer with hydrogen peroxide
are reported to be more effective
than products containing chlorine
compounds and polyhexamethylene
biguanide chloride.

9

2. THE BIO-PRESERVATION OF MEAT

It consists of the control of Nisin determines a
pathogenic and spoilage significant inhibition of the
microbiota by competitive growth of L. sakei on
microflora and natural vacuum-packed sliced ham
molecules. with a shelf-life extension.
Bacteriocins, for example, are Enterococcus faecium and L.
ribosomally-synthesized, sakei, bacteriocin producers,
antimicrobial peptides or prevent ropiness due to L.
proteins, which are active sakei, whereas nisin inhibits
towards other bacteria. the activity of L. carnosum in
Bacteriocinogenic cultures and cooked pork loin.
specific bacteriocins added to These bacteriocins are heat
cooked meat are capable of stable and resist to
preventing slime production. pasteurization, and possible
Nisin is a bacteriocin produced to add bacteriocins to the
by L. lactis subsp. lactic and it meat before the cooking
inhibits the growth of Gram- process.
positive organisms, including Bacteriocins are also involved
bacterial spores. in developing active
It is not a toxic substance if it packaging devices, creating
is ingested, it does not an effective surface with
determine cross-resistance antimicrobial effects.
with medical antibiotic Bacteriocin-activated, plastic
molecules and it is degraded films for food packaging have
by the intestinal tract. been developed for the
storage of hamburgers, hot
dogs, frankfurters and
cooked ham.

10

CONCLUSION

Meat spoilage and product shelf-life is an important
challenge for all the experts gravitating around this
area.
The spoilage due to ropy slime-formation has
influenced the marketing of vacuum packed meat
products and the use of this technology.
The presence of ropy slime-producing bacteria and their
associated sensory abnormalities lead to high direct
financial losses (waste product) and indirect (such as
product selection, disinfection of contaminated
surfaces and non-delivery at destination).
Although food security is likely to be guaranteed, the
macroscopic appearance of the product at the time of
packaging is particularly unpleasant, making it
unsuitable for further processing or marketing.
Food industries and productions must be supported by
research, creating a strong link between discoveries and
applications.

11

REFERENCES

Maria F. Iulietto, Paola Sechi,
Elena Borgogni & Beniamino T.
Cenci-Goga. (2015). Meat
Spoilage: A Critical Review of a
Neglected Alteration Due to
Ropy Slime Producing
Bacteria, Italian Journal of
Animal Science, 14:3, 4011, DOI:
10.4081/ijas.2015.4011

To link to this article:
https://doi.org/10.4081/ijas.2015.4011

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12