Cooked/Raw Handling Survey of Delicatessen Products - October–December 1997

October December 1997

OBJECTIVE

To determine the rate or extent of carry over of bacteria from raw product to cooked product not normally undergoing any further processing, by food handler contamination due to suspect procedures.

Background

Environmental Health Officers are constantly advising operators to wash hands between cooked and raw food serving, to have separate instruments for each to minimise cross-contamination. Microbiological proof of contamination is not known. This survey could provide that supporting evidence

SURVEY

A food handler was requested to supply a sample of raw meat eg. Chicken, after which from that same food handler a sample of cooked meat was requested. Note was taken of technique and whether there was a change of equipment or operator.

The survey was conducted from October - December 1997 and consisted of 85 samples (39 raw, 46 cooked) from 40 separate food outlets. On occasion more than one cooked product was sampled.

Samples were purchased as consumer items over the counter and taken to the microbiology unit (ACTGAL) to be analysed.

Most of the products were brought into the ACT chilled and the retailer prepared those products for eg. slicing, packing and making sausages prior to display or sale. Many of the foods are potentially hazardous which means that at the correct temperatures over sufficient period of time pathogenic bacteria may grow easily on them. The samples overall hygiene quality was assessed as shown below in Table 1 by the Standard Plate Count (SPC), Escherichia coli (E.coli) and Coagulase positive staphylococcus (Coag +v staph) analysis and for specific food pathogens such as Salmonella and Listeria monocytogenes (L.monocytogenes).

Table 1

 

Test Organism

Good

Poor

Unacceptable

SPC

<50-1000

1000-10,000

>10,000

E.coli

<2 #

<2-1000

>1000

Coag +v Staph

<50 #

<50-1000

>1000

Salmonella Spp

Not detected*

-

Detected*

L.monocytogenes

Not detected*

-

Detected*

 

Table 1 shows the surveys acceptability criteria for the cooked foods to be sampled.

# Units expressed in terms of colony forming units (cfu) per gram.

* Organism not detected in 25 gms.

RESULTS

Raw samples

Table 2

Result of Tests by Food Type

No of raw samples containing bacteria

 

Food Type

Total Samples analysed

High SPC

E. Coli

Staph

Salm.

L.Mon

Raw Chicken

22

1

12

1

3

3

Sausages

9

2

2

-

-

2

Red cod fillet

1

-

-

-

-

-

Green prawns

1

         
Bacon

6

1

-

-

-

-

 

Table 2 shows evidence of raw products harbouring a variety of pathogens, all proven to cause food poisoning if not handled and prepared safely.

Handling practices observed

A total of 46 samples of cooked products were analysed to determine if they were safe to eat and assess how well they had been handled - any evidence of cross-contamination.

Of all cooked samples tested, 39 (85%) complied with the food safety surveys acceptability criteria and were unlikely to cause food poisoning.

Of all food premises visited 17 (42%) showed signs of poor food handling as shown in figure 1.

Those improper handling practices have the potential to result in the cross contaminate of cooked products.

Figure 1: % by types, of food handling practices observed on the food premises.


Figure 1: % by types, of food handling practices observed on the food premises.

TABLE 3

Result of Tests by Food Type- Cooked Meats

 

Food Type

(cooked)

Total samples analysed

Food Safety

(based on microbiological levels)

Handling Practices Observed

(based on microbiological levels)

   

Good

Poor

Unacceptable

Good Poor Unacceptable
Ham

28

27

1

 

27

1

 
Turkey

7

3

 

4

6

 

1

Cooked Chicken

5

4

 

1

5

   
Cooked sausages

1

1

   

1

   
Devon

2

1

 

1

2

   
Twiggy sticks

1

1

   

1

   
Corned beef

2

2

   

2

   
TOTAL

46

39

1

6

44

1

1

 

Table 3 summarises table 2 and figure 1 with discussions below:

NB. Poor and unacceptable Food Safety results highlights the reason why issues such as cross-contamination need such close attention.

DISCUSSION

FOOD TYPES (cooked)

(a) Ham

Food Safety

A total of 28 samples were analysed, 27 of which were considered safe to eat. One sample exceeded the survey acceptability.

Food Handling

One sample suggested poor food handling by the presence of presence of Staphylococcus aureus with low SPC. This was probably transferred to the food after cooking/curing process by poor food handling eg. wiping nose or scratching body part and then handling the food.

(b) Turkey

Food Safety

A total of 7 samples analysed, of which were considered safe to eat, 4 unacceptable - contained high SPC and 1 sample Listeria Monocytogenes.

Food Handling

One sample indicated poor food handling which suggested cross-contamination between raw and cooked food might have taken place.

Note: this particular sample was sliced on the same slicer immediately after being used to slice raw products and tested positive for L.monocytogenes.

(c) Cooked Chicken

Food Safety

A total of 5 samples analysed, 4 of which were considered safe to eat, 1 unacceptable - contained high SPC count.

(d) Devon

Food Safety

One sample unacceptable - contained high SPC count.

CONCLUSION

This survey indicates that there is a potential risk of cross-contamination into cooked products if care is not exercised.

The 42% of premises observed to have poor handling practices gives a fairly good indication of the relative potential for cross-contamination.

RECOMMENDATIONS

Refer recommendations document.

BIBLIOGRAPHY

Australia and New Zealand Food Authority, Food Standards Code, incorporating amendments up to and including Amendment 38, April 1998.

Food Act 1992 (ACT), reprinted as at 31 January 1996.

ACKNOWLEDGEMENTS

Sampling Officers: Ralph Anthony

Sample analysis: Microbiology, ACT Government Analytical Laboratory.

Report: Ralph Anthony