In the last 15 to 20 years, great efforts have been made to tackle salmonella in poultry, reducing the number and sources of infections to human consumers, particularly although not only in the European Union. These efforts have brought rewards; and the incidence of cases of food poisoning traced to salmonella from poultrymeat and eggs are gradually declining, although it is clear that producers and processors cannot afford to be complacent.
A recent report from the European Food Safety Authority (EFSA) published in December 2006 illustrates the extent of human cases of food-borne disease in 2005. The good news is that salmonella infections have decreased by 9.5% compared to the previous year but there were still more than 176,000 reported cases in 2005. The study also confirms a decrease in salmonella contamination in eggs over recent years. The bad news is that campylobacter caused more food-borne disease in humans than any other pathogen, with more than 197,000 cases in 2005, 7.8% more than the previous year.
The European Commission announced new regulations for the control of salmonella in eggs last year, details of which are outlined later in this article. From 2008, there will be serious consequences for both farmers and countries in the EU who are not successively reducing the prevalence of salmonella bacteria in and on eggs. After 2010, eggs contaminated with salmonella will have to go for processing, and this will adversely impact the profitability of the business.
The sources of salmonella contamination are many and varied, and this magazine has covered many measures for the control of this pathogen, both on farms and in processing plants in previous articles over many years. Feed Hygiene Live from silo to trough' was the title of a special exhibition at the EuroTier 2006 trade show. It brought some new ideas to the attention of visitors, which will also interest readers of this magazine.
Feed as part of the food chain
Feed production in the EU is governed by an ever-increasing number of regulations, the latest of which establishes feed production as a part of the food production chain. Feed producers are obliged to introduce the concept of Hazard Analysis Critical Control Points (HACCP) and to ensure traceability. The EU feed hygiene regulation covering these areas took effect a year ago. The details such as feed treatments and setting of upper limits for particular pathogens have been left to the governments of the individual Member States.
The so-called feed scandals' of recent years have originated in undesirable substances, such as dioxins, that have been incorporated in the feed, rather than by potential pathogens that multiply in it. Certain fungi and bacteria, on the other hand, live and multiply in the feed and among the major concerns in this group are salmonella, campylobacter and Escherichia coli. The first two of these are food-borne pathogens particularly associated with poultry products. The salmonella family of bacteria are almost ubiquitous and have been detected in most feed raw materials. Furthermore, they tend to be found in clusters and so control of their numbers must become part of the routine in feed production process. This is technically achievable although a word of warning is appropriate at this point: sampling and testing has shown that Salmonella enteritidis was found on the pedals of a truck delivering feed to a farm that was free from salmonella. This experience highlights the importance of HACCP throughout the feed production process from raw materials to the feeder in the poultry house.
Solutions on show in Hanover
Feed hygiene live from silo to trough' at the EuroTier show offered German suppliers the opportunity to present their latest innovations to help stop feed becoming the source of contamination likely to cause harm to poultry and/or consumers. This area was not intended to cover all the options for pathogen control in poultry feed but rather to give a flavour of some of the newer options to aid in the delivery of safe feed to all farm livestock.
Starting with clean feed
Standard processes during pelleting, expansion and extrusion effectively decontaminate feed of potential pathogens. Mash feed, common for layers, is not subjected to these processes and contamination can remain in such feeds. The maximum temperature reached and also the length of time that it is maintained are important factors in the efficacy of decontamination. Suppliers of feed technology have successfully marketed so called hygienisation/conditioning systems' for some years, based on the addition of steam. Whilst these are effective, poor pellet quality results if too much steam is applied and so these machines tend to operate at a lower temperature.
Amandus KAHL presented the High Temperature Short Time (HTST) process in Hanover, which involves the production of heat by friction from mechanical action, rather than relying on steam. Their expanders and extruders control the temperature accurately, without excessive moisture. The company showed pictures illustrating the effects of the HTST process on the microstructure of feed ingredients and on the destruction of E. coli bacteria.
Feed silo hygiene
Producing a clean feed is a good starting point but there is little point in achieving this if the feed can be contaminated by being stored in a feed silo or bin with pockets of old, musty or contaminated feed. Much attention is now paid to the design of feed silos to eliminate corners where feed can become lodged and form a source of infections for future loads.
Menno Chemie-Vertrieb participated in the special exhibition with a silo-cleaning robot. The German Agricultural Society, DLG, had independently tested Menno's Silo-RoBoFox system, a mobile cleaning and disinfection robot for feed silos. The spray unit is mounted on a vertical spindle held between mounting plates at the top and bottom of the silo. The spray unit rotates around the spindle and can be raised and lowered so that the nozzles can spray onto the whole internal surface of the silo. A special cleaning foam (Menno Clean) and disinfectant (Venno Vet 1 super) have been developed for this system. After the chemical treatments, the silo is dried with warm air.
The DLG test on this system indicated that it was effective in cleaning the silo and the microbe numbers were reduced by up to 5-log units. The robot was awarded a Silver Medal for Innovation at EuroTier.
Milling and mixing system
German company, Buschhoff had on display its Widomix-Umwelt, an automatic milling and mixing plant for feed producers. In a four-stage process, the grain is first cleaned to remove foreign bodies and dust. Next, a fully automatic filter system reverses the rise in temperature during the milling process, helping to minimise the build-up of condensation, and it also removed dust. The mixer has been designed for easy cleaning, with a large hatch door. The final stage is a system to blow the feed up to 250 metres to the silo.
Feed transport to the birds
Clever design is also needed in the system carrying feed from the silo to the feed trough or feeder. The elimination of pockets and dead areas where feed can become trapped is key to supplying birds with clean and fresh feed. ACO Funki was displaying its drive unit as an example of how good design can contribute to feed safety. The drive unit is self-cleaning and no feed is left in the pipes. The company offers all the elements necessary to transport feed mash, pellets or crumbles from the silo to the feeder in poultry house at a rate up to 1250kg/hour.
Not forgetting water line hygiene
Although not strictly a measure relating to feed hygiene, Agravis was featuring the concept of hygiene through the water system. Whilst this is particularly applicable in wet feeding systems for pigs, poultry farmers also need to be reminded that water can be a source of contamination and pathogens to their birds. The company recommends that water from the mains or well is tested at least once a year to check that it is free of contamination from heavy metals, other minerals or pathogens.
This company offers its special dosing pump system Desintec H2O Clean as well as a range of chemicals to clean and disinfect the water lines thoroughly. Recommended between flocks is a four-stage routine. The first phase involves a period of 30-60 minutes of alkaline cleaning using Desintec AH-tec, followed by a clean water flush. This should be followed with a 60-minute disinfection period (Desintec WHR-aktiv plus), followed by another thorough flushing of the system with clean water.
New EU targets for egg producers
New legislation to reduce and control the prevalence of salmonella in poultrymeat and eggs was announced by the European Commission at the beginning of August last year.
By 2008, EU member states will have to work towards targets to reduce the number of laying hens infected with salmonella by a minimum percentage each year. Steeper targets have been set for those countries with higher levels of salmonella:
Monitoring of salmonella levels in all member states and in different categories of poultry farms had been carried out, and the results were published by the European Food Safety Authority (EFSA). They found salmonella levels in laying hens to range between 0 and 79% across the EU.
The target is to reduce the levels of salmonella in eggs to less than 2% across the EU. There is a strong incentive to comply with the latest targets. Under the Zoonoses Regulation, it is foreseen that eggs from salmonella-infected flocks will be banned from sale as table eggs from 2010. This will mean that eggs that fail the test after 2010 will have to be processed before sale, adding significant additional costs to the producer and member state.
The national authorities were given six months from the date of adoption to submit national control programmes to the Commission for approval and EU funding, and so all responses should have been received by the beginning of February 2007.
Similar targets were set for breeding hens across the EU in 2005, and separate targets will be set by the Commission to reduce the levels of salmonella in broilers, turkeys and pigs in the coming years.
Harmonised rules on control measures
Also in August last, the Commission adopted a regulation setting out the rules for certain control measures used to reduce salmonella in poultry. From January 2008, all member states with a salmonella incidence higher than 10% will have to vaccinate laying hens against salmonella, with the aim to reduce the spread of the disease and the contamination of eggs. Only authorised vaccines may be used, and the strains must make them distinguishable from field strains.
EFSA is not recommending the use of antimicrobials for the control of salmonella, except under very limited circumstances.
Latest salmonella scares
A survey carried out by the UK Food Standards Agency in November last year found that more than 3% of imported eggs carried salmonella on the eggshell and the bacteria were found inside a small but significant number of the eggs sampled. Much was made of this news in the newspapers, and consumer confidence was again put on the line. There is more on this issue later in this magazine.
At about the same time in late November, it was announced that 15,000 breeding birds on a farm belonging to a Swedish farmers' co-operative had to be slaughtered due to the discovery of Salmonella senftenberg during a routine check on the farm. The farm supplied more than one quarter of the chicks and hatching eggs to the leading broiler producer in Sweden, a company that also makes a major contribution to other Scandinavian markets. Sweden has a zero-tolerance policy towards salmonella, in that no eggs, poultrymeat, pork or beef may be offered for sale in the country if they have tested positive for salmonella.
