Process control

Food safety concerns relate to three categories of hazard: physical, chemical and biological. Some physical hazards (e.g. any extraneous objects such as metal, glass, etc) may cause illness or injury to a person consuming the product. Meat inspection procedures are generally effective in detecting and removing physical hazards. However, sampling and testing programmes are required to monitor for the presence of chemical (e.g. dioxin) and microbial hazards (e.g. microbial agents). Some microbial agents (e.g. bacteria, fungi) may have the ability to multiply on, or in meat. Each group of these hazards, if consumed, may have a major significance for public health. For example, the detection of various bacteria (e.g. E. coli, Salmonella) on the carcass may suggest faecal contamination of meat, primarily during processing. Water, used during processing may be contaminated either with such bacteria or by human viruses of public health concern (e.g. caliciviruses, rotavirus) – hence the requirement to use clean water.

Measures are required to be taken at all points in the farm to plate continuum to include production, transport, slaughter, processing, storage, retail and food preparation (Hogue,

et al., 1998) to ensure the microbiological safety of foods. Systematic gathering of reliable testing data related to the occurrence, elimination, prevention and reduction of foodborne pathogens (Kvenberg and Schwalm, 2000) is seen as an essential element for controlling the microbial hazards of concern (Swanson and Anderson, 2000). However, improving the microbiological quality of foods alone is insufficient since food-processing technologies cannot provide absolute assurance of the absence of pathogens. Given that food can be recontaminated, producers are required to adhere strictly to good hygiene measures by following GHP, GMP, and implementation of HACCP along the whole food

chain (Panisello et al., 2000). The main driving force of the HACCP system is continuous evaluation of the hazards (Berends and van Knappen, 1999) where microbiological testing plays an important role in the verification of the effectiveness of the plan.

The emergence of E.coli as a human pathogen of public health concern resulted in the

introduction of mandatory microbiological monitoring of meat in the USA. However, it has to be emphasised that, as a part of process control, the meat has been monitored microbiologically in most countries for many years but these programmes were rarely standardised and of no interest to regulators. Containment of microbiological risks is attainable and this goal possibly cannot be achieved by end product testing which is a proven effective strategy when directed towards chemical food safety. Many countries are now developing, or have developed, a range of national standardised programmes to monitor the microbiological status of meat.

Microbiological tests form an integral part of the programme by providing valuable information on critical control points, and trigger actions in the case of non-compliance (Lupien and Kenny, 1998). In the USA, the recently introduced Meat and Poultry Inspection regulations (1996) provide a framework for change (Billy and Wachsmuth, 1997) by improving the safety of meat and poultry products (Schlosser et al., 2000), and establishing pathogen reduction performance standards for Salmonella (Sofos et al., 1999). In addition to the large and medium size establishments (plants), the regulations also apply to very small plants (Mossel et al., 1998). The regulations require countries exporting to the USA, including New Zealand, to adopt the same initiative and embark on the development of microbiological standards within regulatory requirements, and microbiological guidelines to be used by manufacturers or regulators to monitor food manufacturing processes (Harris et al., 1995).

In 1995, the EU Council Decisions 95/409 and 95/411 were designed to regulate the

sampling regime and testing for Salmonella. These requirements now apply to all

Member States, including exporting countries. The EU Directives 64/433 and 71/118 have also been amended to regulate the requirements for testing of meat for certification purposes (Akewrberg and Brannstorm, 1997). Since 1997, New Zealand has conducted microbiological monitoring of red meat. The programme, currently known as the

National Microbiological Database (NMD) covers all red meat primary processors. It includes testing in approved laboratories with the aim to provide scientifically valid data and enable the definition of cost-effective regulatory microbiological criteria that are qualitatively and quantitatively linked to stated public health goals. Freshly slaughtered carcasses, chilled carcasses, primal cuts (outside-hind legs) and cartons of bulk meat are now tested according to standardised protocols for generic E. coli, aerobic plate count and

Salmonella where accumulation of data allows (Hathaway et al., 1999) for:

• development of national performance targets,

• on-going monitoring of national performance and individual premises, and

• provision of scientific data to support design of HACCP plans.

In this respect, USDA-FSIS have recognised New Zealand’s ability to compare performance of individual establishment (premise) by comparing their data with national norms, when discussing the food safety objectives of the United States Pathogen Reduction/HACCP Rule. In light of this, the NMD programme is deemed by the USA as the equivalent to the E. coli testing requirements of the US Rule11. According to the draft

policy on the detection of Salmonella in Meat (January 2000), New Zealand “does not

accept that testing for Salmonella has any direct value as a control indicator for red meat process in New Zealand for the following reasons: (1) prevalence on carcasses is very low; (2) rare isolations are more likely to reflect farm/transport health status, rather than poor process control; (3) the isolation is more likely to be a chance statistical effect than genuine indicator effect, and (4) the lag time for laboratory analysis means that actions are taken well after the initiating event and their value is really only as a tool for identifying trends, unless there is a specific process failure”. New Zealand advocated that

E. coli was a much better process control indicator.

11 _{Dr Roger L. Cook - Memorandum: New Zealand Meat Hygiene Assurance Programme (17 November 2001), Ministry of}