Volume 13: Industry Processes and Controls
1. Introduction
Hygiene, 'sterilisation' and the inactivation of the BSE agent

1.14 The conditions and practices developed to protect human health from the dangers posed by unfit or microbiologically contaminated food are collectively referred to as 'hygiene'. These range from ensuring the general cleanliness of slaughterhouses to testing food samples in laboratories for bacteria and viruses that pose a health risk. Many of these practices have been made compulsory. The layers of food hygiene regulation are examined in vol. 14: Responsibilities for Human and Animal Health.

1.15 Over time, as hazards have been identified and scientific knowledge has accumulated, hygiene practices have become increasingly refined. In the late 1980s, food safety issues took on a high profile following the perceived increasing incidence of microbiological illness such as salmonella in eggs. However, the emergence of BSE presented different problems, and the systems of surveillance and treatment that had been developed to deal with microbiological contamination of food were not effective against the BSE agent.

1.16 The measures introduced to deal with bovine material potentially infected with BSE were designed to control it at the slaughterhouse, before it reached other industries; or to prevent its use, for example in feed, altogether. This was considered necessary because the processing of material by other industries was generally not capable of inactivating the BSE agent. In 1994, the Spongiform Encephalopathy Advisory Committee (SEAC) advised that the minimum conditions necessary to inactivate the most heat-resistant forms of the scrapie agent were autoclaving at 136°-138°C at a pressure of 30 pounds per square inch for 18 minutes. ¹ The Committee noted that the BSE agent responded like scrapie in this respect. ²

1.17 It is important to distinguish 'inactivation' from 'sterilisation', which usually refers in legislation and elsewhere to hygiene procedures designed to prevent microbiologically contaminated food being consumed by humans. For instance, sterilisation under the Meat (Sterilisation & Staining) Regulations 1982 requires that carcasses are:

1. treated by boiling or by steaming under pressure until every piece of meat is cooked throughout;
2. dry-rendered, digested or solvent-processed into technical tallow, greaves, glues, feeding meals or fertilisers; or
3. subjected to some other process which results in all parts of the meat no longer having the appearance of raw meat and which inactivates all vegetative forms of human pathogenic organisms in the meat.

1.18 Sterilisation in the sense of these 1982 Regulations would clearly not meet conditions considered by SEAC to be necessary to inactivate scrapie or BSE.

1.19 The use of the term 'sterilisation' in the Bovine Offal (Prohibition) Regulations 1989 (where it was given the same meaning as in the 1982 Regulations) has the potential to add to the confusion about the use of this term. In this volume therefore, unless otherwise stated, 'sterilisation' is used in the traditional sense, in relation to the prevention of microbiological contamination.