Module 6. Meat and poultry processing

Lesson 25

MEAT HYGIENE AND SANITATION IN MEAT AND POULTRY INDUSTRY

25.1  Meat Hygiene

Meat Hygiene refers to a set of activities that require the implementation of specific standards, codes of practices and regulatory action by the competent authority to ensure “safety and suitability” of the meat the consumers eat.  Hygiene requirements are to be met at different stages of production, processing and transportation and must include hygiene of personnel, slaughter & meat processing equipments and environment. To ensure this, proper cleaning and sanitization practices are to be followed by plant personnel and should include disinfection of meat plant premises, equipments and storage area. Failure in maintaining meat hygiene may pose serious public health hazards and therefore evaluation of meat for meat borne pathogens which can cause diseases of public health importance is very important. Food Safety and Standards (Food Products Standards and Food Additives) Regulations, 2011 also warrant that every product being sold in the Indian market must meet/conform to legal standards of quality.

25.1.1  Principles of meat hygiene

There are three principles of meat hygiene, which are crucial for meat processing operations.

· Prevention of microbial contamination during meat product manufacture by adopting proper cleaning and sanitation practices.

· Minimization of microbial growth in meat products by storing them at a low temperature.

· Reduction or elimination of the risk of microbial contamination by applying suitable heat treatment and packaging systems at the final processing stage.

25.1.2  Possible source of contamination

Failures in maintaining slaughter hygiene, meat cutting and meat handling/transportation and in the hygiene of by-products and additives contribute to quality losses and deterioration of the final processed meat products (Table 25.1).

Table 25.1 Microbiological contamination in the meat processing chain

Carcass contamination during slaughtering	Unavoidable – keep as low as possible.
Meat cutting	No reduction of contamination possible, but further contamination should be prevented.
Further processing	No reduction of contamination possible, but prevent further Contamination and create challenges / hurdles for microbial growth and survival (aw, preservatives).
Heat treatment of final product	Pasteurization (approx. 80°C): Substantial reduction of contamination, but products need refrigeration. Sterilization (above 100°C): Total elimination of contamination, products can be stored without refrigeration (in sealed food containers).

25.1.3  Control measures

Two useful schemes are usually adapted at various levels of meat production:  

· Good Hygienic Practices (GHP) and

· Hazard Analysis and Critical Control Point (HACCP) Scheme.

25.1.3.1  Good hygienic practices in meat processing

Microbial meat spoilage or food poisoning through meat can be prevented if the microbial load/bacterial contamination, which occurs during slaughtering and meat handling, is kept as low as possible.  The key for achieving this is strict meat hygiene including an uninterrupted cold chain throughout the entire meat production and handling chain through the following interventions.

Personnel hygiene

· Wear clean protective clothes

· Washing hands before starting work and repeatedly washing hands during work

· No finger rings, watches, bracelets

· Access to production areas with working clothes only

· Cleaning/disinfection of hands/tools/clothes if there was contact with highly contaminated subjects or abnormal animal parts likely to contain pathogens.

· Fresh wounds through knife cuts etc. must be covered by a water tight bandage.  Workers with purulent wounds are not allowed to work with meat. (Risk of spread of Staph. aureus bacteria).

· Strict toilet hygiene must be observed (removal of apron, hand washing and hand disinfection).  Toilets must be kept clean and must not have direct access to production areas. (Risk of spread of Salmonella). 

· Periodic medical examinations of staff

Hygiene during meat processing 

· Ideally meat cutting/deboning should be carried out in climatized rooms (approx. + 10°C) with low air humidity.

· If visual contamination of meat has occurred during manufacturing, do not try to wash it off but remove it with knives by cutting off superficial meat parts in the case of minor contamination. Discard the meat in case of heavy contamination.

· Do not hose down floor and wall areas or equipment next to meat processing operations or final products with a power hose. (Risk of contamination by aerosol/droplets).

· Never take meat pieces, which accidentally had contact with the floor or other contaminated surfaces, back onto working tables or into meat processing machines.

· Containers for meat, fat, or semi–or fully processed meat products must not be placed directly on the floor but on hygienic stands, pallets etc.).

Hygiene of meat processing premises (design and construction) 

Meat processing facilities must meet the basic hygienic standards in order to ensure and maintain clean and hygienic working conditions:

· Provision of change room for duty staff.

· Wall windows must be positioned at least 2 m high over floor level in order to allow profound washing and disinfection of floors and walls. Window frames should be of non-corrosive material e.g. aluminium or similar materials and must not be painted.

· Walls in all rooms, where meat and by-products are handled, must have smooth and easily washable surfaces up to a minimum height of 2 m in processing plants. Walls should preferably be covered with wall tiles or at least with washable paint.  

· Floors in the mentioned sections must be impermeable for water and reasonably smooth for good cleaning, but anti-slip for workers safety. 

· In order to facilitate proper cleaning, the junction between floor and walls must be rounded (not rectangular)

· Rooms for meat processing should have sufficient ventilation. Air conditioning is only required in meat cutting/deboning rooms (10 - 12°C).

· Supply systems for electrical wiring and pipes for hot and cold water as well as for compressed air should not hamper cleaning operations and be out of reach of possible dirt contamination. Insulations for hot water pipes must have smooth surfaces and be washable.

· Openings for ventilation must be bird- and insect-proof.

Equipment hygiene

· Equipment should have proper sanitary design and construction. Designs must allow easy and profound cleaning and avoid any accumulation of difficult to remove organic matters. They should make use of food grade construction material in designing food contact surfaces and equipments and should allow easy cleaning after processing operations.

· Stainless steel must be used for all food contact surfaces e.g. working tables, meat hooks (at least their parts contact in meat), blades of knives, saws, cleavers and axes etc.

· Food grade synthetic materials should be used for meat containers and other utensils

25.1.3.2  Hazard analysis and critical control point scheme (HACCP)

HACCP are factory and product specific strictly sanitary control schemes that shall prevent, detect, control and/or reduce to safe levels of accidentally occurring hazards to consumers’ health. Despite GHP in place, accidental hazards cannot be ruled out and may occur at any processing step of the individual meat product. Specifically for meat processing plants, such hazards may be provoked by failures such as:  batches of incoming raw meat materials with abnormal tissues or heavy contamination, breakdowns in refrigeration, failure in cooking/sterilization operations, abnormal pH or a_w in raw or finished products, errors in levels of application of curing salts and other additives, technical problems in sealing of vacuum packages or cans with the risk of recontamination. HACCP schemes serve as additional alarm systems in the interest of consumer protection to prevent such problems occurring.  In case potential hazards should occur, they can be detected, contained or eliminated at any stage.

25.1.4  Food poisoning through micro-organisms present in the meat

Food poisoning sets alarming situation for consumers. After consumption of meat contaminated with food poisoning bacteria, food poisoning results in severe illness with consumers needing intensive and costly medical treatments. Type of food poisoning observed due to bacteria are of two types, ie.

· food borne infection or 

· food borne intoxication.

Bacteria that cause food borne infections, cause sickness through microbial metabolic substances i.e. toxic substances released by the living microorganisms inside the human digestive tract. The best known examples of food borne infections are those caused by Salmonella bacteria and entero-pathogenic form, mostly type O157: H7 residing in faecal material, Listeria monocytogenes, Campylobacter jejun and, Yersinia enterolytica. The Norovirus group can be responsible for food infections with similar, mainly gastro-intestinal symptoms, as bacterial food infection agents. 

Microorganisms causing food borne intoxications produce and release the poison during their multiplication in the food. Upon ingestion by consumers of such food, which was heavily intoxicated outside the human body, severe gastro-intestinal food poisoning symptoms occur. Food borne intoxications are frequently caused by Staphylococcus aureus, and Cl. botulinum.  Moulds are sometimes found on the surface of meat products after prolonged storage. Mold produce two types of toxins i.e. Aflatoxins (toxin of Aspergillus flavus) and Ochratoxin (toxin of Penicillium vividicatum).

25.2  Cleaning and Sanitation

Generally cleaning refers to removal of visible, physical/chemical dirt and to some extent bacteria from the equipment surfaces, sometime from products itself and from the processing environment. On the contrary, sanitization term is used with disinfection of the product or product contact surfaces by all killing spoilage and pathogenic microorganisms in order to avoid all possible risks of microbial contamination. Inactivation of microorganisms requires antimicrobial treatments, carried out in food industries through hot water or steam or through the application of disinfectants or sanitizers.

25.2.1  Cleaning procedures

The first step in floor and equipment cleaning is to physically remove scrap, i.e. coarse solid particles, with a dry brush or broom and shovel. This is usually referred to as “dry cleaning”. Wet cleaning is followed after removal of physical scrap material. Wet cleaning could be done manually or by using high pressure nozzles. However, this would require water in sufficient quantities.

Cleaning with equipment producing a pressurized steam/water-mix is even more efficient as impact temperatures of approx. 100°C can be achieved. The disadvantage of this method is the intense fog and aerosol formation, which may not only cause unwanted microbial spreading by water droplets (aerosol) but also affect installations and equipment through high humidity and excessive condensation. For these reasons a steam/water-mix is not suitable for meat processing facilities and cold or hot pressurized water cleaning is preferred.

A relatively new cleaning method for the food industry, in particular the larger-scale plants, is foam cleaning.  Water foam containing detergents and other cleaning agents is sprayed on wetted walls, floors and surfaces of equipment. The foam does not immediately run off but clings to the surfaces.  This allows a longer term contact on the surfaces to be cleaned.  After a sufficient impact period (min. 15 minutes) the foam is washed down with water (water hose or low-pressure water spray). As no high pressure water spraying is needed for washing off the foam, the spreading of water droplets (aerosol) in the room to be cleaned is minimized.

25.2.2  Cleaning agents

Traditional cleaning substances/detergents for manual use are alkalines, such as sodium carbonates (Na₂CO₃, washing soda). These substances are efficient in dissolving proteins and fats, but may cause corrosion in tools and equipment, if their pH is 11 and above.

Ideal detergents should have the following desirable properties:

· Wetting and penetrating power-must wet, penetrate and dispose soil and remove it from walls of equipments.

· Emulsifying power

· Saponifying power

· Deflocculating power

· Sequestering and chelating power

· Quick and complete solubility

· Should be non-corrosive to metal surface

· Economical

· Stability during storage

· Should be mild on hands

· Should possess germicidal action

In Meat industry, various types of detergents and cleaners are used and each one has one or more limitations.  These are presented in table 25.2:

Table 25.2 Common detergents & sanitizers used in meat industry

Detergent	Functions	Limitations
1. Alkalies: a) Sodium hydroxide b) Sodium carbonate c) Sodium bicarbonate d) Sodium silicates e) Sodium phosphates	Digest, disrupt or dissolve soil especially protein, act as emulsifier, bactericidal agents, generally used at 0.2 - 2% (NaOH)	i)  Some of these have poor solubility and wetting power ii) NaOH corrosive towards AI, Tin and Zn especially at higher concentration. (>2.0%)
2. Acids: a) Nitric Acid b) Sulphuric Acid c) Hydrochloric Acid d) Phosphoric Acid e) Acetic Acid	Remove hard deposits such as water stones, such deposits do not dissolve in alkalies, generally HNO3 (0.5%) Phosphoric acid (2.0%) used	Strong acids are corrosive to metal surface and dangerous also
3. Complex Phosphates: a) Tetra sod. pyrophosphate b) Sod. tripolyphosphate c) Sod. tetraphosphate d) Sod. hexametaphosphate	Water softening, soil displacement by emulsification, peptization prevention of redeposition of soil	Excellent but unstable in hot solution and in presence of strong alkalies.
4. Chelating Agents: EDTA (Ethylene diamine tetra acetic acid)	Sequestering, water softening, removal of mineral deposition.	--
5. Wetting Agents: a) Anionic (sod. salt of various complex organic materials b) Non ionic e.g. teepol	-- Wetting and penetrating properties in soil -- Stable dispersion -- Emulsion formation	QAC are expensive.

Alkaline cleaning agents are generally suitable for removing organic dirt, protein residues and fat, while acid cleaning agents are used particularly for removal of encrusted residues of dirt or protein or of inorganic deposits (“scaling”) such as waterstone, milkstone, lime etc. On the other hand, Neutral cleaning agents have much less effect than alkaline or acid cleaning agents, but have mild impact on skin and materials and are useful for manual cleaning of smooth surfaces without encrusted dirt. In practice alkaline and acid cleaning substances should be used alternatively.

25.2.3  Disinfection techniques

The elimination of microorganisms is achieved through disinfection, either by using

· hot water (or better steam) or

· chemical disinfectants.

Chemical disinfectants are preferred for most applications in the meat industries as they are easy to use and do not involve the risk of accidents or other negative side effects such as damage to equipment by generating high humidity or water condensation, which may occur when using steam. Best results are achieved when chemical disinfection is preceded by intensive dry/wet cleaning.

25.2.4  Disinfectants for the meat industry

 Disinfectants should be effective and rapidly acting in killing microorganisms. In principle the following groups of substances are generally used as disinfectants:

1. Chlorine containing compounds e.g. Na/Ca hypochlorite or chlorine gas, has a corroding effect on equipment.

2. Aldehydes (used in animal production, e.g. Formaldedyde) Phenoles / Kresols (used in medicine, households Alcohols (used in medicine, e.g. skin) Alkalines (pH 10 or higher) (e.g. NaOH, used in animal production) Acids (some organic acids used in food industries). Quaternary ammonium compounds Amphotensids (used in food industries, as not corrosive) Low efficiency on spores. They have effect on cell walls, not corrosive, odourless, additional cleaning properties (surfactant)

3. Oxygen releasing compounds e.g. Peroxide compounds (H₂O₂) Per-acetic acid (use in food industries). Penetrate into cells, good effect on all microorganisms including on  spores and virus, odourless, may be corrosive in concentrations >1%

An example of the optimal combination of disinfectant commercially used is  

· organic acids

· surfactants (= surface active agents)

· peroxide compounds

The organic acids, apart from their sanitizing effect, decrease the pH as some disinfectants are more efficient at lower pH. The surfactants assist in penetrating organic material. The peroxide compounds have the direct antimicrobial effect by coagulation and denaturation of proteins (virus) and penetration through cell walls causing cell destruction (bacteria).

25.2.5  Cleaning and disinfection (sanitation) schemes 

· Several daily disinfections (by hot water or chemicals) are necessary for hand tools, meat saws and cutting boards.

· Daily disinfection is useful for dismantled equipment such as parts of grinders, fillers, stuffers, etc. 

· Disinfection once a week is recommended for other equipment and floors and walls of processing and chilling rooms.

25.2.5.1  Cleaning and disinfection plans

Specific cleaning and sanitization plans should be developed for specific processing areas eg. Meat storage, processing etc. An example of such plan is given in table 25.2 for disinfection of meat processing equipment, in this case for a meat grinder. This type of equipment is an integral part of almost every meat processing line.  Meat grinders require particular careful and frequent cleaning and sanitation, as the output product minced meat is hygienically very sensitive.

Table 25.3 Cleaning and disinfection plan

Equipment: Meat grinder

Pre-cleaning	Potable water Temp.:  40-50°C Pressure:  20-30 bars
Cleaning	Daily Agent: A Concentr.:  1.0% Temp.:  40-50°C Time:  20-30 min pH: approx. 12	1 x monthly Agent:  B Concentr.: 1.5% Temp.: 40-50°C Time:  20-30 min pH: approx. 1.8
Rinsing	Potable water Temp.:  30-50°C Pressure:  5-10 bars
Drying
Disinfection	2 x weekly Agent: C Concentration.:  0.5% Temp.:  30-40°C Time:  30 min pH: approx. 5.7	3 x weekly Agent:  D Concentr.: 1.0% Temp.: 30-40°C Time:  30 min pH: approx. 10.2
Rinsing	Potable water  Temp.: 30-50°C Pressure: 5-10 bars

Agent A: Alkaline cleaning substance (Source: Heinz and Hautzinger, 2007)

Agent B: Acid cleaning substance

Agent C: Disinfectant

Agent D: Disinfectant chemically different from C and supplementing impact of C