Microbiological Analysis of Canned

Foods

Objective :

Cause of spoilage

Types of canned foodLow acid-pH greater than 4.6 Acid pH 4.6 and below

Meats Tomatoes

Seafood’s Pears

Milk Pineapple

Meat and vegetable Mixtures &"specialties"

Rhubarb

Corn Sauerkraut

Soups Pickles

Vegetables Berries

Asparagus Citrus

Experimented samples

Experimented canned food samples

Type of canned food

Taken Samples Acidic type

Fish Processed tuna fish Low acidic (pH > 4.6) Formulated food Dried self stable chips N/AFats & oils Butter oils, Vegetable ghee N/AVegetables Preserved corn in sugar

liquorLow acidic (pH > 4.6)

Milk Condensed milk Low acidic (pH > 4.6)Cocoa, Chocolate Chocolate liquor N/AMeats Precooked beef Low acidic (pH > 4.6)Pickles Olive picklesMushroom Preserved mushroom in

salt liquorLow acidic (pH > 4.6)

Poultry product Precooked chicken meat Low acidic (pH > 4.6)

Can preparation :

Physical examination :

APC counting

EAPC (estimated aerobic plate count) of different samples

Sample Range /g or ml

EAPC per ml

EAPC per gram

Quality

Tuna fish 5 X 10^6

1.08 X 10^11 108,000,000,000

Worst quality

Chips 1 X 10^2

4.4 X 10^8 440,000,000 Very bad quality

Butter oil 1 X 10^5

1.15 X 10^11 11,500,000,000

Worst quality

Vegetable ghee

1 X 10^7

7.8 X 10^8 780,000,000 Bad quality

Corn 1 X 10^3

3.2 X 10^2 320 Good quality

Condensed milk

1 X 10^5

3.8X 10^2 380 Good quality

Chocolate 1 X 10^6

1.02 X 10^7 10,200,000 Bad quality

Pickles 1 X 10^4

1.07 X 10^9 1,070,000,000 Worst quality

Mushroom 1 X 10^2

3 X 10 > 05/g Excellent quality

Chicken meat

5 X 10^5

1.24 X 10^7 12,400,000 Bad quality

Subcultures

Biochemical tests :

Citrate test

Nitrate reduction test

Lactose broth test

Indole test

Motility test

Results of biochemical testsSam-ple

Gram stain

Oxidase

Catalase

Urease

MR

VP

Citrate

Ni-trate

In-dole

H2S-TSI

Sucrose

Motility

Detected Microbe

Fish + rod + + + - - - + - - - non

Bacillus spp.

Fish -rod (curved

+ + - - - + + - non

Pseudomonas aeruginosa

Fish +cocci

+ + - - + - + - - - non

Micrococcus

Fish +cocci

- + - - - + + - - AG non

Staphylococ-cus spp

Fish - cocci

- + - - - + + - A non

assumed

Fish +cocci

+ - + + - + + - - A M assumed

Fish -rod + + + + - - - - - A M Alcaligens Corn -

cocci+ + + + - + - - - M assumed

Corn - cocci

+ + + - - - + - - M assumed

Corn - cocci

+ - + - - - - - - non

assumed

Corn - rod + + + - - + - - - non

Sample

Gram stain

oxidase

catalase

Urase

MR

VP

Citrate

Nitrate

In-dole

H2S-TSI

Sucrose

Motility

Detected Microbe

Milk -cocci

- + - + - - - - - - non

assumed

Milk +cocci

+ - - - - + + - A non

assumed

Milk - rod + - - + - + + - A M Salmonella spp

Ghee - cocci

+ + + - - + + - - A non

assumed

Ghee +cocci

+ + + - - + - - - non

assumed

Ghee +cocci

+ - + - - - + - A M assumed

Mushroom

- cocci

+ - + - - - + - A non

assumed

Pickl-es

- rod + - - - - + + - G A M assumed

Pickl-es

- rod + - - - - + + - G - non

assumed

Pickl-es

+cocci

+ - + + - - + - G A non

assumed

Sample

Gram stain

oxidase

catalase

Urase

MR

VP

Citrate

Nitrate

In-dole

H2S-TSI

Sucrose

Motility

Growth on SDA plate

Fish fungi + + + - - - + - - AG non

yes

Fish fungi + + - + + + + - - - non

yes

Fish fungi + + + - - - + - - A non

yes

Ghee fungi + + + - - + + - - A non

Yes

Mushroom

fungi + - - + - + + - G A non

Yes

Mushroom

fungi + - + - - + + - G A non

yes

Sensitivity tests results :

Decision