The invention is directed to the process for the decontamination of contaminated food products, in particular surface contaminated food products, in particular food products of animal origin.

Decontamination is an important process for improving hygiene of food products of either plant or animal origin and in reducing carcass spoilage. The major cause of spoilage is due to accumulation of microorganisms, in particular bacteria. Of the animal carcasses processed for food products, poultry carcasses have been found to have the highest accumulation of bacterial loading, which is mainly due to the way the animals are processed.

Decontamination of animal carcasses involves the application of a substance at a specific step during the slaughter process in order to reduce the microbial contamination. Article 3(2) of Regulation 853/2004 of the European Parliament and Council specifies hygiene rules for foods of animal origin. The authorization of the use of any substance, other than water, to remove surface contamination from food products of animal origin, requires that it be approved in accordance with this regulation.

The European Food and Safety Authority (EFSA) has issued a guidance document (EFSA, 2006) which points out major components and data required to demonstrate that a substance intended to be used for the removing microbes from the surface of food products of animal origin is safe and efficacious. Three main points to consider in determining the suitability of a substance are the safety of the substance, whether use of the substance would cause antimicrobial resistance and efficacy. A further consideration is the environmental impact of such substances when discharged and whether they pose an environmental risk.

The use of substance(s) for decontamination treatments is regarded by the Scientific Panel on Biological Hazards (BIOHAZ) to be efficacious when reduction in numbers of pathogenic target bacteria is statistically significant when compared to the control (e.g. water). Further that this reduction also causes a reduction of related human illness (EFSA, 2008a).

Although no approvals have been currently granted within the EU, countries such as USA, Australia and Canada have permitted a range of substances to be used as antimicrobial agents. The following are a few examples.

Aqueous chlorine, or more sodium hypochlorite solutions are widely used in the treatment of food products, in particular carcasses. However, it becomes less effective in alkaline conditions and in the presence of high levels of organic material. Chlorine dioxide is more effective than aqueous chlorine in removing microorganisms from poultry carcasses and does not have the same disadvantages. Further it is also less reactive with organic compounds such as fatty acids and their esters ("Handbook of food preservation", edited by M. Shafiur Rahman, Marcel Dekker Inc., 2007). However, the use of antimicrobial substances containing chlorine can lead the formation of chloro- organic compounds, several of which are persistent, bioaccumulable or carcinogenic.

Peroxyacids is a substance commonly used for treating a range of food products including bovine and poultry carcasses. In particular, using a combination of peroxyacids with a low concentration of 25 to 40 ppm in chiller water was shown to be effective against microbes. This substance is a preferred alternative to antimicrobial agents comprising chlorine due to their good stability in the presence of organic material and that it decomposes to environmentally by-products ("Antimocrobials in food, 3 ^rd edition", P. Michael Davidson, John Nikolaos Sofos, Alfred Larry Branen, 2005). One of the main disadvantages of peroxyacids is their high rate of hydrolysis during storage at room temperature which leads to a loss in their effectiveness as antimicrobial agents.

Inorganic phosphates, hydrogen peroxide and ozone are also used in the surface decontamination of food products and in particular carcasses.

Trisodium phosphate is a substance officially accepted and widely used for decontaminating poultry carcases, since it does not perceptibly alter the food product. Typical concentrations used are from 10-12 % in aqueous solutions ("Handbook of food preservation", edited by M. Shafiur Rahman, Marcel Dekker Inc., 2007). However, there are concerns associated with discharging phosphorous compounds in the environment, as this can lead to algal blooms and disturbance of aquatic environments.

Washing carcasses with ozonated water does not cause visual defects or changes in sensory properties, such as flavour, in the treated products. However, the reduction in microorganisms is poor and it does not extend the shelf life ("Handbook of food preservation", edited by M. Shafiur Rahman, Marcel Dekker Inc., 2007).

Hydrogen peroxide is known as a very effective against a wide range of microbes and is a safe means of decontamination for food products. The minimum effective dose for poultry being 0.5 % (v/v) in water. At this concentration, a temporary bleaching and bloating of the carcasses is observed ("Handbook of food preservation", edited by M. Shafiur Rahman, Marcel Dekker Inc., 2007). Typically concentrations used are 3 % hydrogen peroxide. In a recent paper by H.S. Lillard and J. E. Thomson (Journal of food Science, 48, pages 125-126, 2006), it was reported that hydrogen peroxide

concentrations of up 12,000 ppm was required to significantly reduce microbes on poultry carcasses. The carcasses were bleached and bloated using this treatment.

US-A-4 683 618 describes a method of removing bacteria from poultry carcasses by deluging with water, spraying with an atomized high velocity solution of baking soda and water, deluging with water again, then spraying with an atomized high velocity solution of baking soda and water again, followed by spraying with an atomized mist of 3% hydrogen peroxide and lastly deluging with water.

US-A-5 264 229 describes a process for reducing bacterial count of an animal based food product and increasing the shelf thereof by introducing hydrogen peroxide and surface active agents into the chiller water to wash off bacteria on the surface of the food product. The agents described are alkylaryl sulfonates, sulfates, sulfonates of oils and fatty acids, sulphate of alcohols and sulfosuccinates.

US-A-5 208 057 describes a process for butchering and disinfecting fowl, wherein said fowl is treated with water comprising of a bromide and an antioxidant selected from a list including hydrogen peroxide.

The decontamination of chicken carcases with a hydrogen peroxide solution stabilized with glycerol was studied by C. L. Wagenaar and J. M. A. Snijders (International Journal of Food Microbiology, 91, pages 205-208, 2004). They reported that a 3 % w/w solution was more effective in reducing colonisation of microbes than lower concentrations and that the appearance and "bloom" of the carcasses were unaffected by the treatments.

The use of a mixture comprising peroxyacetic acid, octanoic acid, acetic acid, hydrogen peroxide, peroxyoctanoic acid and 1-hydroxyethylidene- 1,1-diphosphonic acid has been approved for the use as an antimicrobial agent in treating carcasses in the USA (see Code of Federal Regulations - Title 21: Food and Drugs, Part 173 - Secondary Direct Food Additives Permitted in Food For Human Consumption, Subpart D - Specific Usage Additives, § 173.370 Peroxyacids). For the treatment of poultry carcasses, the maximum concentrations in the antimicrobial mixture for peroxyacids is 220 ppm as peroxyacetic acid, hydrogen peroxide is 110 ppm and l-hydroxyethylidene-1, 1- diphosphonic acid (HEDP) is 13 ppm. The disadvantages of this mixture are that it is a complex mixture comprising more than two components and the short shelf life of the antimicrobial agent due to the instability of the peroxyacids.

US-A-2005/0109981 describes aqueous decontamination

formulations that have pH values of less than 9. It is suggested that a lower pH value, i.e. preferably in the range of 7-8 is preferred. Also the amount of chemical compounds in these formulations is high, typically 12 wt.% or more. RU-C-2 207 036 describes a method for decontamination of sugar and/or starch. No pH of the mixture is disclosed, but since it is intended to stay in the sugar/starch mixture and since it contains both KOH and an acid, the pH will be low, viz. around 7 or 8.

CN-A-101 703 452 describes a disinfecting, itch-relieving hand lotion. It contains a humectant, menthol and ethanol, which would make it unsuitable for decontaminating food products.

The present invention relates to the use of an improved process which is very simple, effective and efficient for the decontamination of food products. Surprisingly it was found that a high pH, viz. of 10 or more, results in activation of the oxidant, such as hydrogen peroxide.

Thus the invention is directed to a process for the decontamination of contaminated food products, comprising applying an aqueous antimicrobial solution to the surface of the food products, wherein said aqueous

antimicrobial solution comprises an oxidant and an alkaline compound, wherein the solution has a pH of at least 10. The present invention uses a combination of an oxidizing agent and an alkaline component. The two products combined create a synergistic effect whereby very fast

decontamination, e.g. in a matter of seconds, of the environment can be obtained. Because the present invention provides a very effective

decontamination, microbial activity of the decontaminated products is very low, as reflected by a low plate count. Thus improved shelf life of the decontaminated products is obtained, which is an important benefit of the present invention.

In accordance with the invention is that the amount of chemicals is very low, viz. it only needs a limited number of compounds of in principle two (although other components may be added), which are also present in low concentrations. This is highly advantageous because the amount of

composition that needs to be rinsed off in a subsequent rinsing step is consequently also limited, thus resulting in saving of time and rinsing solution.

Preferably the oxidant is an oxygen radical forming molecule, in particular hydrogen peroxide or ozone and more preferably hydrogen peroxide.

The alkaline compound is selected from the group comprising of calcium hydroxide, sodium hydroxide or potassium hydroxide, and preferably is calcium hydroxide.

In a preferred embodiment, the aqueous antimicrobial solution comprises a hydrogen peroxide concentration from about 300 to 2500 ppm (all amounts mentioned herein are by weight, unless specified otherwise). The calcium hydroxide concentration is preferably from 0.1 to 1.0 wt.%, more preferably 0.15-0.25 wt.%. The pH of the resulting solution is at least 10, preferably from 10 to 12.

Optionally, after the application of the solution in accordance with the invention an aqueous solution comprising an acid, such as lactic acid is applied to the surface of said food products to neutralize the antimicrobial solution.

Preferably, the surface of the contaminated food products is then rinsed with water.

Appropriate methods of applying the aqueous solutions to the surface of the food product include dipping, immersion, spraying, foaming and gelling. In a preferred method, the food products are dipped in the aqueous solutions for 4 minutes or less, more preferably 2 minutes or less and even more preferably 1 minute or less. Surprisingly very good results have been obtained on dipping the food products for about 10 seconds. The temperature of the solution is generally no greater than 40 °C, preferably it is around carcass temperature (35 to 40 °C).

Alternatively, the aqueous solution is sprayed onto the surface of the food product. Parameters such as pressure, temperature and duration affect how efficiently the microorganisms are removed from the surface of the food product. Spray pressure is important because it may affect how much contamination is mechanically removed. The minimum spray pressure can be as low as 25 psi, however more effective results can be obtained due to the mechanical action of the spray on the surface of the food product at pressures greater than 50, 100, 150 psi and more preferably the spray pressure is greater than about 200 psi.

Typically spray action is best at a temperature of around 35-45 °C, e.g. about 40 °C. However if increased spray pressures are used, then the solutions can be applied at a lower temperature and still remain effective in removing the microorganisms.

Effective spray duration is at least 10 seconds, while improved effectiveness can be achieved by spray duration of about 30 seconds.

Surprisingly we have found that a microbial total plate count is reduced to a value of less than 10 ³ per gram product and may be even as small as zero. The invention is effective for all relevant microorganisms, in particular to enterobacteria, such as salmonella, camphilobacter, etc.

As used herein, the phrase "food products" refers to all types of animals and plants, wherein the forms of the animal, include the carcass, muscle, fat, organs, skin, bones and body fluids and like components that form the animal. Animals suitable to be processed for food products include poultry, mammals, fishes, reptiles, amphibians, snails, clams, crustaceans, or other edible forms of seafood. Plants suitable to be processed for food products include fruits, vegetables and edible fungus. As used herein, the term "carcass" refers to a sacrificed animal prepared or being prepared for harvesting or recovering of food products of animal origin. The carcass can be processed further, such as skinned, headless, or the like.

As used herein, the term "microorganism" refers to any noncellular or unicellular (including colonial) organism. Microorganisms include all prokaryotes. Microorganisms include bacteria (including cyanobacteria), lichens, fungi, protozoa, virinos, viroids, viruses, phages, and some algae. As used herein, the term "microbe" is synonymous with microorganism.

The process according to the invention has been found to be suitable for the decontamination of food products, particularly poultry and food processing apparatuses.

The composition of the invention is preferably free of at least one of humectant, menthol and ethanol, more preferably it is free of all these ingredients.

The invention is now elucidated on the basis of several examples, which are not intended to limit the scope of the invention.

Examples

Normal chicken pieces, consisting of breast fillets and thighs were purchased from a supermarket and stored at room temperature for five days so as to obtain a high contamination. An antimicrobial solution was prepared comprising of 2 gram calcium hydroxide and 5 ml of 50 % hydrogen peroxide in 1 liter of water. The chicken pieces were dipped in the antimicrobial solution for different durations ranging from 10 sec to 1, 2 and 4 min respectively. The temperature of the antimicrobial solution was 35 °C.

Hygicult agar slides were contacted with the chicken pieces and then incubated at 28 °C for three days. The incubated slides were then compared to the model chart to determine the microorganism density. The results are provided in table 1 below.

Table 1. Microorganism density for chicken fillets and thighs following antimicrobial treatment

Treatment Chicken Fillet N/cm ² Chicken Thighs N/cm ²

Untreated 80 100

10 sec 0 1

1 min 0 0 2 min 0 0

4 min 0 0

Treatment times of 10 sec and 1 min resulted in no discolouration of the chicken pieces.

Treatment times of 2 and 4 min resulted in a slimy layer on the surface of the chicken pieces. Following incubation for five days, still no microorganism growth was observed.