Food or edible material: processes – compositions – and products – Inhibiting chemical or physical change of food by contact... – Animal flesh – citrus fruit – bean or cereal seed material
Reexamination Certificate
2002-01-16
2003-08-12
Paden, Carolyn (Department: 1761)
Food or edible material: processes, compositions, and products
Inhibiting chemical or physical change of food by contact...
Animal flesh, citrus fruit, bean or cereal seed material
C426S532000, C452S123000, C452S131000, C134S025300, C134S026000
Reexamination Certificate
active
06605308
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the field of disinfectants, and relates more specifically to using hypochlorous acid solutions as pathogen management systems in, for example, a poultry processing system to limit poultry contamination.
2. Background of the Invention
Chlorination is known method for killing undesirable microorganisms. Chlorine may be provided in multiple forms including chlorine gas (Cl
2
), sodium hypochlorite liquid, calcium hypochlorite powder or granules, or isocyurantes. Chlorine gas (Cl
2
) is a relatively cheap and highly effective antimicrobial agent; however, it is also a highly toxic and corrosive gas. Hypochlorites such as NaOCl or Ca(OCl)
2
are a much safer alternative, but are considerably more expensive that gaseous chlorine. Finally, hypochlorite solutions (i.e., bleach) may also be utilized, however these are rarely used in large scale Water treatment applications because they are bulky and expensive. Regardless of the chlorine source, hypochlorous acid (HOCl) and the hypochlorite ion (OCl
−
) are the final desirable antimicrobial products.
One method of forming HOCl occurs when Cl
2
is dissolved in water. The reaction proceeds according to the following equation:
Cl
2
+H
2
O
HOCl+H
+
+Cl
−
(1)
Another method for producing HOCl uses metal hypochlorites dissolved in water. The reaction proceeds according to the following equation:
NaOCl+H
2
O
NaOH+HOCl (2)
This method is generally utilized by common household hypochlorites and generates HOCl on a relatively small scale.
HOCl is a weak acid and will dissociate. In aqueous solution, HOCl and OCl
−
are generally present in a pH dependent equilibrium:
HOCl
H
+
+OCl
−
pKa=7.53 (3)
At low pH, HOCl is the predominant form, while at high pH, OCl
−
predominates. The HOCl form is about 80 times more effective than OCl
−
for killing microorganisms because HOCl crosses cell membranes easier than the hypochlorite ion. Accordingly, it would be desirable to control the pH of the chlorinated solution to increase the antimicrobial effectiveness of the chlorination process.
One particular use of chlorination is to kill undesirable microorganisms in poultry processing systems. Since much of the poultry processing involves moving the bird on conveyers and human contact, provisions must be made to keep both the equipment and personnel sanitized.
For example, Salmonella is one of the most important causes of foodborne disease worldwide. In many industrialized countries the incidence of salmonellosis in humans and the prevalence of Salmonella in many food products have increased significantly over the last twenty years. Salmonella bacteria have a broad host-spectrum, and can be isolated from a wide range of animal species, including birds and reptiles. The animals usually are healthy carriers, and contaminated feed plays an important role in the epidemiology 5 of salmonellosis. Salmonella can survive for a long time in the environment. Humans are usually infected through consumption of contaminated foods of animal origin. However, other food such as fresh produce, seafood and chocolate have also been implicated in outbreaks because of cross-contamination, use of contaminated water, use of manure as a fertilizer, presence of animals or birds in the production area or other factors.
In a typical poultry processing operation, freshly laid fertile eggs are collected and incubated. After they hatch, chicks are delivered to farms, reared until ready for slaughter and then transported to a processing plant. At the plant, the process of slaughtering includes several phases from unloading and shackling the live birds to grading and packaging the carcasses. Then, carcasses are shipped and distributed chilled or frozen while some poultry carcasses are used for portioning and/or to produce a variety of raw or processed products. The microbiological condition of poultry carcasses is highly dependent on the manner in which animals are reared and slaughtered. The microbiological condition of live birds influences the microbiology of the products and the live animals are the principal source of microorganisms found on poultry carcasses. At the processing plant, the conditions of slaughtering will further influence the extent to which processed poultry will be contaminated.
There are many sources of contamination during poultry processing. Commercially grown poultry flocks are collected on the farm, placed into crates, transported to the processing plant and slaughtered on the same day. Contaminated crates can be a significant source of Salmonella and
E. coli
on processed carcasses. Contamination of feathers with microorganisms of fecal origin increases as birds are confined in crates for transport to the plant and microorganisms in feces and on feathers can be spread from bird to bird within the crates. Stress of transportation may amplify the pathogen levels. In one study, fecal droppings collected in broiler houses about one week prior to slaughter were contaminated at a rate of 5.2% while Salmonella was found in 33% of the samples collected from live-haul trucks at the processing plant.
During hanging, as feathers, feet and bodies are contaminated with a variety of bacteria, wing flapping creates aerosols and dust, contributing to contamination of the unloading zone and transmission of pathogens at this stage.
Stunning and killing have few microbiological implications, although electrical waterbath stunning may lead to inhalation of contaminated water by the birds and microbial contamination of carcass tissues.
During scalding, soil, dust and fecal matter from the feet, feathers, skin and intestinal tract are released into the scald water and thus provide a significant opportunity for cross contamination. A large variety of bacteria, e.g. Salmonella, Staphylococcus, Streptococcus, Clostridium spp. have been isolated from scald water or from carcasses or air sacs immediately after scalding.
Bacterial survival in the scald water is influenced by scald temperature and time. The lethal effect of water held at 60° C. (hard scald) used for carcasses intended for water chilling is measurable and greater than the lethal effect of water held at lower temperatures, e.g. 50-52° C. (soft scald) as used for carcasses that will be air chilled.
It has also been demonstrated that scalding results in modifications to the poultry skin: removal or damage of the epidermal layer, exposing a new surface for contamination which is smoother and less hydrophobic, exposure of microscopical channels and crevices. During and after scalding, the skin surface retains a film of scalding water which contains organic matter and large numbers of bacteria. Some of these bacteria may adhere more easily to the modified surface of the skin. Some may be retained in the channels or crevices on the skin surface as well as in the feather follicles. During the following stage of defeathering, there may be entrapment of bacteria in the channels, crevices and follicles. When entrapped, the bacteria may be difficult to remove by subsequent procedures, including mechanical and chemical decontamination treatments; they also display greater heat resistance.
Defeathering with automatic machinery may be expected to cause considerable scattering of microorganisms in particular via aerosols. Early findings, from work being carried out in the United Kingdom, indicate that these aerosols from defeathering can be reduced by altering the design of the equipment. Conditions inside the machines are favorable to the establishment of a biofilm and colonization by pathogens, in particular
S. aureus
which can survive, multiply and become indigenous to the equipment. Defeathering has been recognized as a major source of carcass contamination with
S. aureus
, Salmonella, Campylobacter spp and
E. Coli
. Several studies have established that the microbial populations on poultry carcasses reflect the microbiologi
Shane Tommy J.
Swain Harvey
Deveau Todd
Paden Carolyn
Thomas Kayden Horstemeyer & Risley LLP
Tomoco
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