Spoilage of canned food- food microbiology

Food Microbiology

1. VIVEKANANDHA
ARTS AND SCIENCE COLLEGE FOR WOMEN
VEERACHIPALAYAM -636303 SANKARI SALEM TAMIL NADU
DEPARTMENT OF MICROBIOLOGY
SUBJECT: FOOD MICROBIOLOGY
TOPIC: CANNED FOOD
SUBJECT INCHARGE: SUBMITTED BY :
DR: R. DINESH KUMAR JAYAPRIYA MANIKANDAN,
ASSISTANT PROFESSOR III-BSC MICROBIOLOGY
DEPARTMENT OF MICROBIOLOGY DEPARTMENTOF MICROBIOLOGY
VIAAS , SANKARI VIAAS, SANKARI

2. CANNED FOODS

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•Nicolas Appert (17 November 1749-1June 1841)
was a French confectioner and inventor who, in the
early 19
th
century, invented airtight food
preservation.

•Appert, known as the “Father of food science ”
described his invention as a way “of conversing all
kinds of food substances in containers”.

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•Canning is a method of preserving food
in which the food contents are processed and
sealed in an airtight container.
•Canning provides shelf life typically ranging
from one to five years, although under specific
circumstances it can be much longer a freeze
dried canned product such as canned dried lentils
could last as long as 30 years in an edible state.

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•Cooling water
•Improper canning temperature
•Improper lacquering
•Improper seaming

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•May be chemical or biological or both
•Chemical spoilage : Hydrogen swell
•Major chemical spoilage generally in acid food
•Due to formation of hydrogen gas gets released during the reaction of the
acid of the food of the food on the iron of the can

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•Is favoured by:
1.Increase in acidity of food
2.Temperature of storage
3.Imperfection in the lacquering or
tiny of the interior of the can
4 . Poor exhaustion
5.Due to the presence of soluble
Sulphur and phosphorus compounds

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•Others defects caused by the interaction of steel base and can and the
food:
1. Discoloration of the interior of can
2.Discoloration of food
3.Production of off- flavour in food
4.Loss of nutritive valve

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•Due to the survival of the organism after the administration of the heat
treatment.
•Leakage of the container after canning permitting the entrance of the
organism.

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•Spoilage by mos’ are divided into those caused by thermophiles and those by
mesophiles
•3 most important kind of biological spoilage of commercially canned food:
1.Flat sour spoilage
2.TA spoilage
3.Putrefaction
4.Hydrogen swell

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•Results from under Processing
•Chief types of spoilage are :
Flat sour spoilage
TA spoilage
Sulphide or “sulfur stinker” spoilage

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•Occurs chiefly in low – acid foods
•Ends of the can remains flat during souring or the development of lactic
acid
•Usually caused by species of Bacillus, especially facultatively thermophilic
B. Coagulans ; B. Stearomophiles
•Produces acid without gas
•Source: plant equipment’s, eg. Blanchers, sugar or soil

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•Short form of thermophilic anaerobes not producing hydrogen sulphide or
caused clostridium thermosaccharolyticium
•Thermophilic spore forming anaerobe that forms acid and gas
•Swelling of the can results due to mixture of CO2 and H2 may result
bursting
•Usually has a sour or cheesy odor.

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•Organism :Desulfotomaculum nigrificans
•Obligate thermophilic , less heat resistant than those of flat sour and TA
spoilage
•Leads to the formation of H2S
•Low acid foods such as peas and corns

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•Organism : spore forming bacteria of genera Bacillus and Clostridium
•Results due to under –processing

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•Cl. Butyrium and Cl. Plasteurianum: butyric acid type fermentation,
swelling of the can due to H2 and CO2 produced
•Cl. Sporongens ; Cl. Putrefaciens and Cl. Botulinum :proteolysis or
putrefaction

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•B. Subtilis and B. Mesentericus: low acid canned foods ;poorly evacuated
cans ; mostly seafood, meats and evaporated milk
•B. Polymyxa and B. Macerans : canned peas, asparagus, spinach, peaches
and tomatoes
•Entrance through a leak in the can.

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•Non-spore formers
•Streptococcus thermophilus ; Lactobacillus spp and Leuconostoc spp –
hetero- fermentation
•Micrococcus spp; Microbacterium spp - gas formation
•Coliforms- gas production which swells the can
•S. Faecalis and S. Faecium – spoilage on storage

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•Fermentative yeasts- swelling of cans by CO2
•Film yeast – surface growth
•Presences indicates recontamination or under – processing plus poor
evacuation
•Jams, jellies, syrups, jellied pickled pork etc..

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•Common cause of the spoilage of home – canned foods
•Entrance : through the leak in the seal of container
•Jams, jellies,, marmalades, and fruit butters (sugar concentration – more
than 70 percentage)
•Aspergillus spp, penicillium spp and citromyces spp
•Byssochlamys fulva – pectin fermentation

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•Flipper: Can filled with mild pressure ;one of the end becomes convex ;
may be the initial storage of hydrogen swell or due to over – filling or
under – exhausting
•Flat : normal ends of can ( slightly concave )
•Springer: mild swell at one or both ends of can ; bulged end if pushed
stay concave or an opposite flat end pop outs

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•Best flavour and nutrient quality are ensure
•A convenient and affordable way to incorporate more fruits and
vegetables into the diet
•Help you make wise choices
•May increase fibre intake
•Cans are lightweight, durable, and easy to store, carry and dispose

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•High sodium content
•Environmental impact
•Limited variety and freshness
•Potential or quality variation
•Cost considerations
•Risk of spoilage

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