NZ Food Safety Authority. Guidelines for the Production of Uncooked Comminuted Fermented Meat (UCFM) Products

Fermentation

During fermentation, lactic acid bacteria provided by the starter culture preparation utilises sugar within the meat and sugar added to the batter to produce acid which lowers the pH of the batter and prevents the growth of pathogenic bacteria. During its growth, the starter culture also produces flavour compounds, enzymes, and other compounds which prevent the growth of other bacteria.

The rate of acid production and pH fall depends on several factors, including the number and type of lactic-acid bacteria in the starter

culture, the fermentation temperature and the amount and type of fermentable sugar. Effective temperature control is critical to the safety of the final product. The validated fermentation temperature must be followed, and it must be monitored since deviations can significantly

affect the lethality of the process and E. colireduction.

It is important that the product reaches a pH below 5.2 (or other validated pH) within a specified period to control the growthof pathogenic microorganisms including Staphylococcus aureus and pathogenic E. coli. Slow or delayed fermentation may allow the growth of Staphylococcus aureus, Clostridium botulinumand other bacterial pathogens. This pH reduction also induces protein coagulation and reduction in the meat’s water holding capacity which favours water release and facilitates drying (Toldra, 2006).

In general, higher fermentation temperatures require shorter fermentation times, and faster pH falls to prevent pathogen growth. For example, at the lower temperature range of 21°C to 24°C, fermentation can take as long as two to three days. At 28°C to 32°C (range commonly used in NewZealand), 16 to 24 hours of fermentation is usually required. In the United States, where faster overall production time are preferred, the fermentation temperature can be as high as 37°C to 40°C for as little as 12 to 18 hours (Hutkins, 2006).

To ensure that the pH decreases within the required rate, pH readings must be taken from each batch during the fermentation period. pH monitoring is further discussed in section 7.3 of this guide.

Beef and venison

UCFM manufacturers who use New Zealand beef or venison can use the national profiles for E. coli from the National Microbiological Database (NMD) programme, which is administered by the New Zealand Food Safety Authority (NZFSA).

Under the NMD programme, slaughter premises processing cattle, calves, lamb/sheep, deer, goats, chickens and ostriches, test meat for E. coli at least weekly, and their data is recorded in a national database. NZFSA is, therefore, able to provide a national profile for these meats which is likely to reflect most meat produced in New Zealand. Manufacturers of UCFM products can simply use the national profiles and determine the required inactivation of E. coli from these values.

Table 2 provides E. coli values for beef and venison from the national profiles as of 30 March 2009. NZFSA recognizes that rare contamination events can occur that multiply the usual counts by 1000-fold, and therefore the values have been based on the 98th percentile of national data, not the maximum.

Table 2 also shows the required inactivation based on the 98th percentile. A value rounded to the nearest whole log count has also been provided for simplicity. This rounded inactivation number of 2-log includes a safety margin to try to take account of the measurement of uncertainty and sampling. Therefore, the validated UCFM process must be capable of achieving a 2-log reduction in the number of E. coli when New Zealand beef or venison is used as the raw material.

Table 2: E. coli Count (98th percentile) and Required Inactivation

Species	E.coli (log cfu/g)	Inactivation number (log)	Rounded inactivation number (log)
Beef	1.3	1.3	2
Venison	1.77	1.75	2

Manufacturers may gain more flexibility for their product or process if they obtain meat from known suppliers and can use the suppliers’ own NMD data. For instance, individual suppliers may have an E. coli profile with a 98th percentile less than that of the national profile. Therefore, the manufacturer may be able to apply a process with a lower lethality (i.e. less than 2-log reduction).

Manufacturers who use imported beef will need to obtain E. coli data from their meat supplier, or do their own tests on their incoming raw materials. Testing should be based on a sampling plan which will provide sufficient data over a certain period so that the manufacturer and regulator can have confidence that the validated process can consistently reduce E. coli to specified limits. The 98th percentile of that data should be used to calculate inactivation requirements.

Pork

Pork has not been previously included in the NMD programme. The implementation of the NMD for pigs will start in August 2009, therefore, NMD data is not currently available for domestic pork. When sufficient data becomes available, manufacturers of UCFM products can use the national profiles and determine the required inactivation of E. coli from these values, similar to the approach discussed for beef and venison.

For imported pork, and in the absence of NMD data for domestic pork, manufacturers may use their meat supplier’s own data, when this is available. The 98th percentile of that data should be used to calculate inactivation requirements, as discussed in the previous section. Manufacturers may also do their own tests for their incoming raw materials. Testing should be based on a sampling plan which will provide sufficient data over a certain period so that the manufacturer and regulator can have confidence that the validated process can consistently reduce E. colito specified limits.

A recent survey of domestic and imported pork showed that the 98th percentile of E. colicounts was below 100 cfu/cm2. Data from Australia and Sweden show similar results. It would therefore be appropriate for manufacturers who do not have sufficient data of their own to target a 2-log E. colireduction for the initial validation of their UCFM process. However, these manufacturers are expected to do their own tests on their incoming imported pork raw materials and build up sufficient data, or use the NMD national profiles for domestic pork when it becomes available. The UCFM process must be revalidated when results show that the 98th percentile for E. coli counts is greater than 2-log

Link to Full report

http://www.foodsafety.govt.nz/elibrary/industry/guidelines-production-uncooked-guide/ucfm-guide-july-2009-final.pdf

IMPORTANT DISCLAIMER

Every effort has been made to ensure the information in this report is accurate.

NZFSA does not accept any responsibility or liability whatsoever for any error of fact,omission, interpretation or opinion that may be present, however it may have occurred.

Website

A copy of this document can be found at:

www.nzfsa.govt.nz/processed-food-retail-sale/standards/oucfm-food/index.htm

Review of Guideline

This guideline will be reviewed, as necessary, by the New Zealand Food Safety Authority. Suggestions for alterations, deletions or additions to this guideline, should be sent, together with reasons for the change, any relevant data and contact details of the person making the suggestion, to:

Assistant Director (Production and Processing)

New Zealand Standards Group

New Zealand Food Safety Authority

PO Box 2835

Wellington

Phone: (04) 894 2500

Fax: (04) 894 2643