Microbiological Quality of Manufactured and Smoked Meats

April - June 1999

Report prepared by Geoff Millard

Objective

This survey was designed to determine if the microbiological status of Manufactured Meats available in the ACT had changed since a previous survey. The survey was expanded to include Smoked Meats.

Background

Manufactured and Smoked Meats are widely available in the ACT and this survey was undertaken as a previous survey conducted on Manufactured Meats, between October and December 1997, highlighted some problems with handling, storage and cross contamination.

Standards

The Australia New Zealand Food Authority (ANZFA) Food Standards Code has standards for some of these products.

Standard C1, Part 13, subclause 60 states that Uncooked Fermented Meat products must:

  • have a Coagulase-positive Staphylococci count not exceeding 1,000 Coagulase-positive Staphylococci per gram (g) as examined by Method 3.2 in the schedule;
  • be free from Salmonella in 25 g of the food when examined by Method 4 in the schedule;
  • and
  • In the case of an uncooked fermented comminuted meat product to which clause 60A applies, after fermentation or any other process, be free from Escherichia coli (E.coli) in 0.1 g of the food when examined by Method 9 in the schedule.

Sub clause 61 states that paste or pate which is, or described as, manufactured meat or processed meat must:

(a) be free from Salmonella in 25 g of the food when examined by Method 4 in the schedule;

  • have a Standard Plate Count not exceeding 1,000,000 micro-organisms / g when examined by Method 5 in the schedule;
  • and
  • be free from Listeria monocytogenes in 25 g of the food when examined by Method 6 in the schedule.

There are no microbiological standards for smoked products.

Survey

Between April and June 1999 Environmental Health Officers (EHOs) belonging to the ACT Health Protection Service collected 75 samples from thirteen different establishments. These establishments were intended to represent a cross section of available outlets. The EHOs purchased the meats over the counter, as consumer items and the samples were analysed by the Microbiology Unit of the ACT Government Analytical Laboratory (ACTGAL). The samples covered the range of available products from food-halls, supermarkets, delicatessens and butchers.

Although the ANZFA Food Standards Code give definitions for the different products eg cooked or uncooked, in practice it proved difficult to ascertain whether a product had been cooked or not. Most of the products were purchased loose over the counter where the cooked status was not stated. Some of packaged items also did not state their cooked status. To facilitate the survey, all meats were tested against the full range of tests. The survey collected multiple samples from single outlets and most outlets were only tested once.

All of the samples were assessed for overall hygiene quality by Standard Plate Count (SPC) and Escherichia coli (E. coli) tests, and for specific pathogens by coagulase-positive Staphylococcus (Coag+Staph), Listeria monocytogenes (L. monocytogenes), Salmonella sp and Clostridium perfringens (C. perfringens) tests.

Results

Standard Plate Count (SPC)

Graph 1

 

Standard Plate Count (SPC) graph

The median SPC was 65,000 cfu per gram.

It should be pointed out that a number of the products were described as Salami. These products are usually fermented products with a naturally high SPC. This product does not have an ANZFA SPC criterion and therefore excluded from Graph 1. Seventeen (25.7%) samples had an SPC greater than 1,000,000 cfu/g, thirteen (19.7%) samples had an SPC greater than, 10,000,000 cfu/g, while seven (10.6%) samples had an SPC greater than 100,000,000 cfu/g

A total of five samples of paste or pate were collected and tested. All five pate or paste samples tested for SPC met the ANZFA criteria as their results ranged from 2,500 to 30,000 cfu/g.

Escherichia coli

E. coli was not detected in any of the 75 samples tested.

Coagulase Positive Staphylococcus

Coagulase-positive Staphylococcus was detected in two (2.6%) different manufactured meats Berliner and Pressanello, with counts of 200 and 5,300 cfu/g respectively.

C .perfringens

C. perfringens was not isolated from any of the 75 samples tested.

Listeria monocytogenes

L. monocytogenes was isolated from four (5.3%) of the 75 samples tested. The positive samples were Smoked beef, Smoked turkey, Chicken roll and Pepperoni.

Salmonella sp

Salmonella sp. was not isolated from any of the 75 samples tested.

Discussion

Coagulase positive Staphylococci were detected in two samples i.e. Berliner and Pressanello. The count in the Berliner sample was below the criterion limit. Meanwhile the count in the Pressanello, although exceeding the criterion limit, had not reached a toxigenic level (approximately 50,000 cfu/g). Their presence indicates human contamination and/or storage problems.

L. monocytogenes was detected in four items Smoked beef, Smoked turkey, Chicken roll and Peperoni. Two of these items, the Smoked beef and Smoked turkey, were purchased from the same delicatessen on the same day as loose items. This suggests possible cross contamination. The detection of L. monocytogenes in these ready-to-eat foods is cause for concern.

As previously stated under point 4, as most of the samples were purchased loose over the counter, it proved difficult to ascertain the cooked status of the sample and therefore its compliance with the ANZFA definition for manufactured meat.

In an attempt to compare the results of the 1997 and 1999 surveys, it was decided to apply the ANZFA criteria to all samples irrespective of their cooked status. The exception being for the ANZFA SPC criterion which was only applied to the 12 and 5 pate or paste samples collected in 1997 and 1999 surveys respectively. Where ANZFA criteria did not exist in-house criteria were prepared and used to compare the survey results (See Table 1).

Table 1.

 

Test Criteria

Acceptable %

YEAR

1997

1999

SPC <1,000,000 cfu/ g#

55.5

69.3

E. coli <10/ cfu/g

95.5

100

L. monocytogenes not detected in 25g.

95.5

94.7

Coagulase Positive Staphylococci <1,000 cfu/g

100

98.6

C. perfringens <50 cfu/g*

100

100

Salmonella sp not detected in 25g.

100

100

 

*Not an ANZFA criteria.

The trend from Table 1 is that while the SPC and E. coli results improved the L monocytogenes and Coagulase Positive Staphylococci results had deteriorated between surveys.

Conclusion

The 1999 survey results indicate that a level of public health concern for this ready to eat product still exists.

Bibliography

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

Downlaod

Quality of Manufactured and Smoked Meats