Food HygieneUnit 1: Food Inspection

Topic: Inspection of food items

Practical 7

Food Inspection

An effective food safety system is important.

Inspections are required of– Systems– Processes– Facilities– Products

Importance of food Inspection

Protect the health of populations– Ensure compliance with standards– Prevention/control of FBI

Ensure social stability Promote and maintain trade relations

Food Inspection The critical examination of food using

various methods/techniques:– Observation- blemish, dents, leaks– Palpation – spoilage of fish– Incision- cutting into meats– Auscultation – shaking and listening– Percussion - tapping cans– Organoleptic – smell, taste

Labelling Criteria

Name of product Brand name Weight/volume of product Manufacturer/Distributor Ingredients Dates

Product Dating “Sell by” date

– tells the store how long to display the product for sale. Product should be purchased ahead of this date to allow time for consumption

“Best if used by” date – recommended for best flavour or quality; not a purchase or

safety date. “Use by” date

– last recommended date for use of the product while at peak quality; this is determined by the manufacturer of the product.

“Expiry” date– Recommended by the manufacturer, safety of the product

cannot be guaranteed beyond the indicated date.

Fish

What factors are responsible for fish spoilage?Under what conditions do you purchase fresh fish?

Fish

Freshly caught fish relatively wholesomeDeterioration of quality commence upon leaving waterPrincipal of condemnation is decay

Fish Spoilage Microbiological Reasons Chemical Reasons Physiological Reasons

Microbiological Reasons for fish Spoilage

Several spp. of microbes are always present in surface slime and intestinal tract

Bacteriostasis in live fish

Flesh of life healthy fish sterile

Upon death microbes multiply rapidly and attack tissues

Since microbes survive at low temperatures in the ocean, can resist refrigeration temperatures

Need to store below 4.4 C upon being caught

Physiological reasons for fish spoilage

Glycogen depletion in muscles Little glycogen available to be

converted to lactic acid Limited lactic acid to retard microbial

growth

Chemical Reasons for fish spoilage

Enzymatic action on certain constituent of fish– Autolysis or self digestion

Undesirable chemical substances produced by the growth and activities of bacteria

One such substance is tri-methyl amines– Responsible for the fishy odour in spoilt fish

Oxidation - rancidity

Fish Inspection 1. Oganoleptic

– Appearance– Odour

2. Palpate – consistency– A sand paper feel denotes staleness– Lack of moisture at the surface– Lack of firmness of flesh and elasticity– Odour should not be fishy

Fish

Accept 4.4 C or lower Bright red closed gills Bright clear, bulging eyes Firm flesh Firmly attached scales with

moderate amount of slime Mild ocean/seaweed smell Blood along the b-bone in

visceral cavity bright red Body stiff and tail rigid Surrounded in crushed self

draining ice Carcass sinks in water

Reject >4.4 C Pale pink, dull gray gills, slimy Dull, sunken, cloudy, red rimmed

eyes Dull flesh with missing scales Soft flesh, leaves imprints Lifts from backbone easily Bone alone the b-bone cavity

dark to black with foul odour Limp pliable body Strong fishy or ammonia smell Yellow slime Carcass floats in water

Keeping quality

The less fish is handled the longer it will remain wholesome

Keep fish embedded in finely shaven ice Fish fillet, sliced fish or fish with

exposed surface should not come in direct contact with ice or water– Will result in more rapid spoilage, change in

flavour and appearance

EGGS Eggs usually mean those of hens but

may include those of ducks and turkeys also.

Made up of three main parts:– Shell– White (albumen)– Yolk

Parts of an Egg

Parts of the eggShell Composed mainly of calcium carbonate May be brown or white depending on the breed of chicken Quality, flavour, cooking characteristics and nutritional value not

affected by colour

Air Cell Pocket of air formed at large end of egg Caused by contraction of the contents during the cooling process Increase in size as the egg ages

Shell membrane There are 2 - inner and outer shell membrane Surround the albumin Provide protective barrier against bacterial penetration Air cell forms between these 2 membranes

Parts of the eggAlbumen (white) Major source of protein and riboflavin

Chalazae Twisted, cord-like strands of egg white Anchor yolk in centre of egg Prominent chalazae indicative of freshness

Vitelline (Yolk) Membrane Closer seal which holds the yolk in placeGerminal Disc

Yolk Colour varies with feed Colour doesn’t indicate nutritive value Major source of vitamins, mineral and fat; and ~1/2 of the protein

Air Cell Empty space between the white and the shell at the

large end of the egg.

As a freshly laid egg is cooled, the contents contract and the inner membrane separates from the outer membrane forming an air cell.

As the egg ages, moisture and carbon dioxide leave through the pores and air enters to replace them causing the airspace to get larger.

Air cell is visible at the flattened end of a peeled boiled egg.

Air Space in Egg

– The shell has an air space of less than 1/4” deep

– The air space gets larger with time

Blood Spots Also called meat spots Found on egg yolk and results from the

rupture of blood vessels on the yolk during the formation of the egg or in the oviduct.

Candling can reveal eggs with blood spots As the egg ages, the yolk takes up water from

the albumen and dilutes the blood spots, hence blood spots indicate a fresh egg.

Eggs with spots are fit for consumption.

Bloom Freshly laid eggs have a dull appearance The coating or covering on the egg that

seals the pores. Prevents bacteria from getting into the egg

and reduces moisture loss Washing removes the bloom Protection can be restored from a light coat

of mineral oil.

Conditions that render egg unsound

MICROBIAL– Mold (penicillum, cladosporum)– Pseudomonas – causing black rot or

green rot– Avian TB (rare)– Salmonella – from faeces of the bird

Conditions that render egg unsound

PHYSICAL– Cracked eggs – will decompose quickly– Storage position – storage for a long time

in inverted or horizontal position causing adherence of yolk to shell

– Evaporation – resulting in enlarged airspace

Conditions that render egg unsound

CHEMICAL– Mainly due to enzymic action– Enzymes cause eggs to become watery.– Loss of CO2 changes pH and causes a

transfer of water from the white to the yolk.

– The yolk of a freshly laid egg will stand in a viscous white.

As an egg ages, several changes occur:

Water moves from the white to the yolk The yolk structure weakens The egg whites becomes thinner The air space increases Bacteria may enter through the shell A “bad egg” smell occurs due to the

production of H2S and other compounds

Testing Egg for freshness

Shaking Candling Immersion/Brine test Yolk Index Test

Testing Egg for Freshness

Candling– Hold egg before powerful

light source– Egg quality judged by

transparency– While rotating egg yolk,

albumen and air space are visible

– Albumen is translucent without spots

Stale Egg Albumen becomes dark

and opaque Yolk less visible Enlarged air space

Blood spots due to the growth of microbes/ cracks can be detected

ShakingFresh eggs make no soundStale eggs make a sloppy sound

Testing Eggs for freshness

Immersion/ Brine test Involves floating egg in water

– 10% solu. (2oz salt to 1pt water)

– Fresh egg sinks– Stale egg float in varying positions

Shrinkage of the albumen Carbon dioxide and moisture levels, Replaced by air through pores in egg shell Increased air space

Testing Egg for freshness

Yolk Index Test– Dividing the height by the

diameter of yolk

Cracking egg on a plate

Fresh Egg Rounded yolk Stands up in the

viscous white

Stale Egg

Yolk flattens– weakening of the vitelline

membrane– Absorption of water from

albumen

Thin liquified albumen– Degeneration of the

gelatinous structure

Difficult to separate yolk from albumen

Sour odour detected

Evidence of Unsoundness in Egg

Degree of suitability of the yolk– Adherence of yolk to shell– Dark spots– Disintegration– Colour changes

Depth of air space– >1/4”

Presence of blood spots Presence of discoloured albumen Evidence of the embryo Presence of cracks in the shell Unpleasant odour

Inspection of Egg

Accept 4.4C or lower No odour Clean Unbroken Firm yolk

Reject >4.4C Sulphur smell/off

odour Dirty Broken/cracked

Examination of Egg Colour change, Odour change, packaging,

temperature, physical contamination

Liquid Egg– <4.4C– In tack packages– No signs of thawing

Dehydrated Egg– No caking

Meat

Accept 4.4C or below Beef - bright, cherry red;

aged beef may be darker in colour; vacuum packed may appear purple in colour

Lamb – light red Pork – light pink, firm white

fat Texture – firm and spring back

when touched No odour Package clean and in tact

Reject Above 4.4 C Beef – brown or green Lamb – brown, whitish

surface covering the lean meat Pork – excessively dark colour,

soft or rancid fat Texture – slimy, sticky or dry

Sour/rancid odour Package – broken cartons.

Dirty wrappers, torn packaging, vacuum packaging with broken seals

Poultry

Accept Below 4.4 C No discolouration Texture – firm and

springs back when touched

No odour Package – surrounded

by crushed self draining ice

Reject >4.4 C Purple or green

discolouration around neck; dark wing tips

Stickiness under wings or around joints

Abnormal/unpleasant odour

Smoked fish

Accept Fresh clean, smoky

smell Firm, dry free from

blood stains

Reject Sweaty, soft, slimy

flesh Mould growth Uncharacteristic

smell

Salted Fish

Accept

Fresh, firm, clear, dry

Stored in cool dry place

Should be protected from all sources of contamination

Reject

Soft, moist flesh Pink/green fungal

growth Foul odour Improperly stored Maybe infested with

Lasioderma or other pests

Pickled Fish

Accept Fish covered with

liquor Firm fish Free from blood

stains and broken pieces

Reject Fish partially covered

wit liquor Fish covered with

muddy liquor Fish with a foul/rancid

odour Blood stained flesh,

discoloured Fish broken in pieces

Shellfish Mollusks – soft bodied, protected by

hard shell– Oysters, mussels, clam

Crustaceans – body encased in hard, close fitting shell.– Possess legs, flesh firmer than mollusks– Lobster, crab, shrimp

Shellfish - Oyster Most widely consumed mollusks Require 4-6 years to maturity Thrive best in brackish water

– Can breed in water highly polluted with sewage

– Oyster reflect the bacteriological quality of water

– Oyster can self cleanse in chlorinated water

Shell fish - oyster

Accept

Tightly closed unbroken shell

Outside clean Pleasant odour Sink in water Liquor pH 6-7

If shucked - <4.4 C

Reject

Opened shell- don’t close when tapped

Unpleasant odour Excessive dirt and slime Sticky or dry Floats in water Liquor pH more acidic If shucked - >4.4 C

Lobster

Accept Muscular activities in

tail Odour free Free of dirt and

slime If scalded alive-

shell will have pink colour

Reject No resistance in tail Discolouration under

tail Slimy exudate under

claws Dark colour of the

shell when scalded Foul odour

Crab

Accept Should be accepted

alive Very active No offensive odour

Reject Offensive odour Sluggish dead

Frozen processed foods

Accept Solid frozen -14 to -21 C Ice soft and flaky In tack packaging Clean packages

Reject Evidence of thawing

– Fluids or frozen liquid in case bottom

– Ice crystals– Water stains

Damaged packages Unfrozen foods > 14 C- icecream

Reduced Oxygen Packaged Food

Accept 4.4 C or lower unless

otherwise specified by the manufacturer

If frozen – frozen Packages in tact Use by date evident Acceptable colour

Reject >4.4 C, unless

otherwise specified If frozen- not frozen Torn or leaking

packages Pass use by date Unacceptable colour,

slime, bubbles, and excessive liquid

DairyMilk, butter, cheese

Accept <4.4C Clean, unbroken

packages Fresh characteristic

smell Milk: sweetish flavour Butter: sweet flavour,

uniform colour, firm texture

Cheese: typical flavour, texture and uniform colour

Reject >4.4C Dirty, broken packages Milk: sour, bitter or moldy

taste, ropiness, discolouration, off- odour

Butter: sour, bitter; mold growth; uneven colour, rancid smell

Cheese: unnatural mold, uneven colour, abnornmal flavour and texture

Cheese

Asiago CheeseBlue Cheese

UHT Foods

Accept In tack package In tack seal <4.4C when opened Proper labels Use by date

Reject Leaking, punctured Leaking packages Dirty packages >4.4C after opened No label No use by date

Fresh Fruits & Vegetable

General rejection criteria– Insect infestation– Evidence of mold– Damaged surfaces– Wilting and Mushiness– Discolouration & dull appearance– Unpleasant odours– Unpleasant taste

Ackee Introduced 1778 –

West Africa Noted- 1875 1st documented- 1904

Hypoglycin cpd. Responsible for ackee poisoning

“Jamaica Vomiting Sickness Syndrome”

Freshly picked mature ackee

Ackee Two toxic substances can be extracted from

the fruit– Hypoglycin A & Hypoglycin B

Hypoglycin A, can be found in the aril of the fruit

Unripe fruit has a higher concentration of hypoglycin (x20)

Seed and membrane at the base of the seed are always poisonous

Source: http://www.scq.ubc.ca/the-ackee-fruit-blighia-sapida-and-its-associated-toxic-effects/

Ackee Hypoglycin A is an unusual amino acid Has the ability to significantly reduce

blood glucose levels and induce hypoglycemia

Depletion of glucose reserves and the inability of cells to regenerate glucose leads to hypoglycemia.

Source: http://www.scq.ubc.ca/the-ackee-fruit-blighia-sapida-and-its-associated-toxic-effects/

Ackee

Potential risk behaviours for ackee poisoning include the following:

– Consumption of unripe ackee fruit– Consumption of ackee that has been

forcibly opened– Reuse of the water in which an unripe

ackee has been cooked

Stages in maturity of ackee

Bearing seasons– January to March– June to August

Fruits bear in clusters, turn red on reaching maturity

Split open along the seams with continued exposure to the sun

Ackee maturity guide 1) SMALL UNOPENED

– small, hard, immature, and unopened. Unsuitable for processing or eating.

2) SLIGHTLY OPENED – Slightly open, pod lobes split, seed and aril visible – (Warning: At this stage, the hypoglycin (toxin) is at a

dangerously high level. Fruit can be reaped for racking but not for processing or eating.

3) FULLY OPENED – Fully opened pod: seed and aril clearly visible. Suitable for

processing and eating. 4) ADVANCED SHRIVELLING

– Advanced Shrivelling of pod, onset of spoilage, aril begins to decay or rot.

Ackee maturity guide

Fruit Maturity•Ackee takes 7-8 weeks to attain full maturity

•During weeks 2-3 of fruit development, the fruit doubles in size, after which the fruit increases at a much slower rate

• At full maturity the fruits are pear shaped and acquire a red or a yellow tinge with red colouration

•The pods then open revealing the seeds and 3 fleshy arilli

Inspection of canned foods

Canning is a widely used method of food preservation so the inspection of canned foods is unavoidable.

At least 10%of consignment should be inspected– If >2.5% rejected – action

Canned FoodsIt is important to: – Identify the can contents– Identify the brand– Identify the weight– Condition on the can

Four methods of inspection can be utilized– Observation– Palpation– Percussion– auscultation

Canned FoodsNormal Can Clean appearance Rust free Dent free Stain free Has slightly concave

ends Sound Seams Leak free Labelled Use by date

Abnormal Can Rusty can Dented Bulging (“blown”) Leaking unlabelled

Good can

Observation Look for rusts, leaks, dents, holes, swelling,

soldering defects and presence or absence of labels.

CANS WITHOUT LABELS MUST BE CONDEMNED

Swollen cans are referred to as “blown” Blowing is due to gas production from

microbial action or chemical reaction Check labels or bottom of cans for product

dating

Palpation Degrees of swelling can be detected by palpation, i.e.,

pressing the can between the fingers and thumb of both hands.

If air is inside, it will respond to pressure.

Flipper – earliest stage of spoilage where the can appears normal, but pressure on one end will cause a bulge in the other end. When pressure is release, end regains its normal appearance.

Springer – more advanced spoilage where pressure on one end causes the other end to bulge permanently.

Palpation Bulging does not always mean that the

contents are decomposing, it may be due to:– Insufficient vacuuming– Overfilling– Chemical reaction between can and food

(hydrogen swell) These conditions cannot be determined

unless the can is opened, so err on the side of safety and condemn all blown cans.

Percussion Employment of this method provides a

useful indication of quality. Sound cans will emit a dull note when

tapped If gas is present in a can, it will have a

higher, drum like pitch when knocked

Auscultation This is applicable to canned foods that were not

packed with liquid, e.g., meats. If the contents have deteriorated, a liquid will be

present. DO NOT USE THIS METHOD FOR FOODS

PACKED IN LIQUID Canned foods can deteriorate without gas

production (flat sour)– This cannot be detected without opening

On the basis of the condition of the can, you make your judgment – pass or condemn.

Bad Cans

Bad Cans A. Bulge or swollen at one or both

ends B. Cans dented at seams C. Can showing signs of leaking D. Rusty cans

Assignment Acceptance /rejection criteria for:

– Prepare an inspection form to be used at a receival area of a large restaurant. Design the form in a manner such that there are clear acceptance rejection criteria for any food of choice.

Due: Next Practical session