Lec 2 + 3 semester 9 - Listeria Monocytogenes as FSC and Coagulase + staphylocci as PHC | Quizlet

True or false

Can more than 1 criterion apply too a particular food stuff

True

Example - A food business that produced RTE, chilled smoked mackerel with a shelf life of 20 days must enusre it complies with :

1. FSC for L. Monocytogenes

2. FSC for Histamine

What two FSC microorganisms must a food business comply with when they produced RTE,chilled, smoked mackerel with a shelf life of 20 days

1. FSC for L. Monocytogenes

2. FSC for Histamine

All RTE food needs to be tested for listeria unless it is...

Canned food

Definition of Ready - to - Eat = RTE

RTE means food intended by the FBO for direct human consumption without the need for cooking or other processing effective to reduce to an acceptable level or eliminate microorganisms of concern

What food categories are related to RTE - IMPORTANT

Food category 1.2 +1.3

Ready meals labelled to b reheated are within or outside the scope of 2073/2005 Reg

Outside the scope

Smoked salmon, sandwiches and products not requiring such processing prior to consumption are within or outside the scope of reg 2073/2005

Within the scope

The real active risk of Listeria in RTE Smoked Salmon was ...... out of 100,000 ppl per yr

0.0046 out of 100,000

What type of pathogen is listeria monocytogenes and what can it cause

It's a Food born pathogen that is transmitted and it does not form spores

It may cause human disease

Where can L. Monocytogenes be found

1. Frequently found in the environment, in soil, vegetation and faeces of animals

2. Found in raw foods like fish, raw milk and fresh meat

3. Especially in fish RTE foods

example of Criterion 1.1

L. monocytogenes in RTE foods intended for infants and special medical purposes

RTE baby foods

RTE foods intended for infants less than 12 months old

Examples of criterion 1.2

L. monocytogenes in RTE foods able to support the growth of L. monocytogenes other than those in 1.1

Soft cheese

Smoked Salmon

Prepacked sliced cooked meat

Examples of criterion 1.3

L. monocytogenes in RTE foods unable to support the growth of L. monocytogenes other than those in 1.1

Hard cheese

yogurt

ice cream

Which type of cheese supports the growth of Listeria monocytogenes

A. soft cheese

B. hard cheese

A. soft cheese

RTE foods belonging to Food category 1.1 and 1.3 which DO NOT need to be regularly tested for L. monocytogenes

1. Live Bivalve Molluscs

2. Sugar, honey, confectionary , cocoa

3. bottled water, soft drinks, beers

4. fresh, uncut, unprocessed fruit and veg - excluding Sprouted seeds

5. products heat treated in their final package -foods which have received heat treatment or processing effective to eliminate L. monocytogenes when recontamination is not possible after this treatment

Whereabouts should L. monocytogenes be monitored

Processing areas and equipment

To assess cleanliness of table

you should tale swabs

what is the core temperature of thoroughly cooked food

core temperature 75°C

what is the core temperature of thoroughly reheated food before consumption

core temperature 70°C

what is needed to achieve a 6-D reduction in the number of L. monocytogenes

thoroughly cooking food so it reaches a core temperature of 75°C, is considered effective to achieve a 6-D reduction in L . monocytogenes

The food born pathogen - L. monocytes is regarded as

A. least heat resistant pathogen

B. most heat resistant pathgoen

B. Most heat resistant pathgoen

Can FBOs use alternative time/ temperature combinations

Yes they can use Alternative time/ temperature combinations, as long as they achieve the same lethal effect

examples of scientifically accepted time/ temperature combinations

70°C/ 2 min

67°C/ 5 min

64°C/ 12 min 37 secs

Foods which are reheated for palatability purposes but will not reach a core temp of 70°C are considered ......

RTE

Foods considered RTE are:

1. Foods which are reheated for palatability purposes but will not reach a core temp of 70°C

2. Even if they are labelled with an instruction to wash before consumption eg lettuces

List the 3 categories of RTE with respect to L. monocytogenes - important

1.1 - RTE foods intended for infants and RTE foods for special medical purposes

1.2 - RTE foods able to support the growth of L. monocytogenes, other than those intended for infants and for special medical purposes

1.3 - RTE foods unable to support the growth of L. monocytogenes , other than those intended for infants and for special medical purposes

By default, RTE foods are considered food category 1.2 = able to support growth of L. monocytogenes if......

1. they do not fall into category 1.1

or

2. the FBO can NOT demonstrate they fall into food category 1.3

no support from factors like - pH,aW

Number of samples taken (n=) for :

1. Criterion no. 1.1

2. Criterion no. 1.2

3. Criterion no.1.3

1.1 - n=10 because it must be stricter for infants

1.2 - n=5

1.3 - n- 5

characteristics of food that fall into food category 1.3- unable to support growth of l. monocytogenes - IMPORTANT

Unable to support growth of L. monocytogenes

1. Shelf life is less than 5 days

2. pH is ≤ 4.4

3. water activity aW is ≤0.92

4. pH is ≤5.0 and aW is ≤0.94

5. It is a frozen food

6. Its growth potential is ≤ 0.5 log10 cfu/g

Name 5 factors that affect the growth and survival of L. monocytogenes

1. Temperature

2. pH

3. water activity

4. Salt concentration

5. Atmosphere

Factors that affect the growth and survival of L.monocytogenes

1. Temperature -CAN grow and survive -1.5 - 45°C

Can survive but NOT grow when frozen - 18°C

Optimum temp - 30-37°C.

2. pH - CAN survive + grow pH 4.2- 9.5

optimum pH 7

Can survive but NOT grow pH 3.3 - 4.2

3. Water activity - CAN survive and grow 0.9 - 0.99

Can survive but NOT grow with aw <0.90

4. Salt concentration - Can survive and grow <0.5 - 16

can survive NOT grow > 20

The time before bacteria start to grow is called

Lag phase

How long is the Lag phase for Listeria monocytogenes - IMPORTANT

5 days

If the shelf life of a product is less than 5 days, is L. monocytogenes a threat

No threat

B/c the lag phase of L. monocytogenes is 5 days

In a shelf life shorter then 5 days - listeria can NOT grow

pH range of:

fresh poultry

cows milk

fresh fish

fresh shellfish

fresh poultry - 5.8-6.0

cows milk -6.2 - 7.3

fresh fish - 6.6- 6.8

fresh shellfish - 6.6 - 7.0

What level of water activity will inhibit pathogenic and spoilage bacteria

aW level of < 0.85

inhibit pathogenic and spoilage bacteria growth in food with water

what level of water activity will yeasts and moulds grow

aW level as low as 0.6

what alters the water activity of food

1. Drying

2. freezing

3. Adding solutes or Ions

Approximate water activity of smoked salmon

≥ 0.93- 0.98

Extra examples of water activity in foods

1. distilled water

2. Fresh meats, poultry, fish, eggs

3. cheddar cheese

4. dry and fermented sausages

1. Distilled water = 1.0

2. Fresh meat, poultry, fish, eggs= ≥ 0.98

3. cheddar cheese = ≥ 0.93-0.98

4. dry and fermented sausages = ≥ 0.8- 0.93

Does L. monocytogenes grow in Frozen food

No it does NOT grow in frozen food

- as long as the food remains frozen in this period

what food category should frozen food fall into (in regards to l. monocytogenes

food category 1.3

(unable to grow)

when can frozen food fall into category 1.2. Give an example

When the frozen food needs to be defrosted before consumption and the shelf life of the defrosted food is 5 days or longer

- defrosted foods can support the growth of L. monocytogenes

examples: frozen cheesecake

how can you determine the growth potential of L. monocytogenes

By preforming Challenge tests .

These are specific laboratory studies and specific inoculation of food

they give us the ability to calculate growth potential

growth potential is marked as

Delta (triangle)

If Delta log2 - listeria able to grow

how to undertake a lab test

3 inoculums from 1 product

3 different temperatures

3 different shelf lives

results of challenge test classified as UNABLE to support the growth of L. monocytogenes - 1.3

≤ 0.5 log10 cfu/g

unable to support growth

food category 1.3

results of challenge test classified as ABLE to support the growth of L. monocytogenes - 1.2

> 0.5 log10 cfu/g

able to support growth

food category 1.2

examples of intrinsic properties of food

1. Microbiological quality of raw material

2. food composition

3. pH

4. water activity

5. oxygen availability

examples of extrinsic properties of food

1. Good hygiene and manufacturing processes

2. Storage temperature

3. gas composition

4.. Relative humidity

5. packaging

Shelf life and time for Botulinum toxin formation example

Product : cold smoked trout

inoculum : 10'2 spores of c. Botulinum/g

temp : 4,8,12 °C

time : 7,14,21,28 days

what are the limits for listeria

1.1 + 1.2 - food is able to support the growth of listeria = limit is absence in 25g

1.3 - food is unable to support the growth of listeria = limit is 100cfu/g

two food safety criterions for Histamine - important

1.26 Fishery products from fish associated with high amount of histidine

n= 9 Limit: m-100mg/kg M- 200mg/kg

Limit is 100mg/kg in 9 samples with no samples exceeding 200mg/kg

1.27 Fishery products that have undergone enzymatic ripening treatment in brine matured from fish associated with high amount of histidine - eg Anchovies

n=9

Limit: m-200mg/kg M- 400mg/ kg

Two limits of histamine - important

1.26 = Limit: m-100mg/kg M- 200mg/kg

1.27 = Limit: m-200mg/kg M- 400mg/kg

true/ false

Should fish products obviously contaminated with parasites be placed on the market

false - They should NOT be put on the market

According to health standards and Reg 853/2004 annex III+ Reg 2074/2005 annex II

example of fish parasites

cestodes

giardia

nematodes

trematodes

Microbiological Criteria for fish and fish products - Reg 2073/2005

1. Canned Anchovies

2. Ready to eat chilled smoked mackerel

3. oysters

4. canned tuna

5. cooked mussels

6. cold smoked salmon

example of seafood : Salmonella in cooked crustaceans and moulluscan shellfish

mussels + prawns

example of seafood: Salmonella and E.coli live in bivalve molluscs and live echinoderms , tunicates and gastropods

oysters +clams

example of seafood : Histamine in fishery products from fish species associated with a high amount of histadine

TUNA + sardines

example of seafood:

Histamine in fishery products which have undergone enzyme maturation treatment in brine

manufactured from fish species associated with a high amount of histidine

Anchioves - important