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Cheesemaking is an area of food hygiene that requires particular attention to cleaning. It is not enough to use ordinary detergents in cheesemaking, special detergents are sold to dairies by their dairy products suppliers. This includes the chemicals used for cleaning the pasteurising machines. In fact, a good cheesemaker spends around 50% of his time cleaning.

Cheese can only be made in vats that can tolerate being washed in caustic soda. This means that the only metal that can be used is stainless steel. All vats and stainless steel work surfaces must be washed after each job, after the end of the working day and before work begins in the morning. This also includes milk holding tanks and their pipes which are washed in an internal washing system using caustic soda in water that is heated to 65-70 degrees Centigrade.

The soda is sprayed into the tank by a pump via a rotating sprinkler. After the cycle has worked for the correct period the soda is sent into the drain, the tank is then sprayed by hand to get rid of all soda residue, including sending some through the sprinkler, then filled with an adequate quantity of fresh water which is pumped through the pipes to wash out any soda remaining in them. The pasteuriser is also undergoes CIP (cleaning in place), as soon as the milk has been pasteurised and also at the beginning of every working day before milk is passed through it to be pasteurised.

Cheese dairies usually only work making one type of cheese. However, some “boutique” dairies make a selection of cheeses. It is important to keep the production of cheese that incorporate the use of molds well away from cheeses that do not have molds in them because because it is almost impossible to prevent mold cross contamination. Even a single mold spore in a block of maturing cheese can cause it to go runny and take on entirely different characteristics from those desired and the whole maturation room will be infected with cheese mold spores.

If you make cheeses remember these principles. When making cheeses nothing else should be in the area during the whole process. Personal hygiene is of utmost importance. Hands washed to the elbow in very hot water and detergent, no rings, no watches, no bracelets. Wear gloves whenever handling milk products and change gloves if they are surgeons gloves or wash them frequently in hot water and detergent if they are not disposable ones.

1573Add to Technorati FavoritesI was asked to help solve a problem concerning cross contamination and product quality control in one of the smaller fruit juice factories in our area yesterday. The factory in question has a capacity to produce 72,000 liters of various fruit juices, fruit drinks and fruit nectar and ice teas. The factory basically consists of two departments, a mixing department and a bottling department. The products are either packed in glass bottles, plastic bottles or tetra pak cartons.

All of the concentrates are poured into the 18,000 liter vats via a barrel tipping machine and a suction device for rotoplasts. The concentrates are pumped through a pipe console which directs the concentrates in to one of four vats in the mixing department.

The factory had started producing tomato juice several months ago and since the onset of this production the company has been experiencing problems with the shelf life and color of products. They had tried every way they could imagine to clean the pipes leading into the tanks but to no avail. Tomato paste is very thick and viscose which makes it a difficult product to work with. Tomato paste tends to travel through pipes in pulses and because of this it coats the pipes evenly from the inside. Thinner and less solid substances such as caustic soda solution tends to run along the bottom of pipes and will only reach the top extremities for brief moments. This makes cleaning tomato paste particularly problematic.

I could smell the presence of tomato concentrate coming out of all of the pipes. There was no question that there was a grave danger of the tomato residue in the pipes fermenting. After a little thought this was my solution to the problem:

1) only to use two of the tanks for producing tomato paste. The effect this would have would be to reduce any possible risk by 50% from the outset.

2) to install separate feed pipes into those two tanks for tomato paste. This would leave the pipes for other products uncontaminated by tomato paste.

3) To dilute the tomato paste with 50% chilled water in a 500 liter mixing tank which was already on site.(2 degrees centigrade) prior to being pumped into the tanks. This would cause the concentrate to be less viscose and much easier to clean during the CIP process.

4)To dissemble and to clean the pump on the barrel tipping machine after every use.

5) To dissemble all pipes weekly and to immerse them in caustic soda solution.

6) To clean all pneumatic valves with a special industrial pipe cleaning brush from all directions.

At the end of the meeting with the department head, production manager, head of quality control and the general manager, all my suggestions were accepted and will be implemented within one working week. I will conduct a follow up check one month from today.

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Last Monday morning I received a phone call from the area superintendent of the department of public health. She told me that there was a steady stream of people falling sick due to eating food prepared by one of the large kitchens in our area. She continued to tell me that her department had been through the place with a fine tooth comb but still couldn’t find the source of the contamination. I arranged to meet them at the premises in question the following day to conduct an inspection.

To tell you the truth, I had a pretty good idea what I would be looking for because I had been to that particular kitchen several times in the past and had spotted a few things that seemed problematic. However, I had to make it seem as if I was earning my money so I decided that we would start somewhere quite far from the place that I suspected to be the problem.

We started by taking swabs of everything we saw and asked staff to provide swabs, blood, urine and stool samples. We checked the toilets of staff and diners alike and took swabs from all manner of cooking pots and trays,

I knew that this kitchen was using a type of bread basket within which to thaw meats and fish. The bread baskets were stacked one upon the other and left inside the two degree Celsius anti room of the freezer complex for up to four days. I also knew that the baskets were loaded onto a low level service trolley and brought up to the kitchen. I had known the chef of this kitchen for a number of years and I also knew that it was his practice to unload the baskets into plastic tubs after the lunch had gone out to the dining room. I always made a practice of doing this first thing in the morning before we started on the days chores.

What this meant was that the contents of the baskets were left to warm up from between seven o’clock in the morning until 11 o’clock in the morning. This wasn’t a very good practice. Every chef has his ways but I knew that this was not the exact point I wanted to look at closely. What bothered me were the baskets themselves. I had a word with the chef and asked him to make an exception today and vacate the baskets earlier. What i notices was what I suspected. After rinsing the basket with water to remove the blood I saw that there was a light colored plaque stuck to the plastic. I took a scraper and saw that it came away fairly easily. I took scrapings from all the baskets used that day and then took the baskets to the aluminium washing machine to see what happened.

The man working on the machine proudly took a stack of five baskets and but them onto the machine and presses the operating handle down. The baskets disappeared into the machine for a few seconds and then came out. The worker informed me that this was a very efficient way of washing the baskets. he then placed them back onto the service trolley which had not been washed only sprayed with a water gun and placed the baskets next to the lift ready to by taken back down to the freezers.

The guy in charge of the freezer units the proceeded to re fill them with produce for another day. I had noticed several things, 1) the baskets had not been scrubbed with a stiff plastic brush of Brillo pad with detergent, 2) they had only been rinsed inside the machine which used high pressure but was ineffective due to the fact that the stacking of baskets inside the machine rendered the high pressure ineffective,3) chicken, beef, pork and fish had been set out to thaw in the same tower of eight baskets.

All of this led us to believe that we had quite possibly found the missing link of the food contamination dilemma. What had been happening was that liquid released from the thawing meat and fish had been dripping onto the plaque in the bottom of the baskets which in turn had been dripping onto the neat inside the baskets below. Then we discovered something else. The worker who had been handling the baskets went to work on the dish washing machine that cleaned the crockery and cutlery merely wiping his hands on a towel and removing his plastic apron before going onto the dish washing machine. It was his job to remove the clean cutlery off the dish washing machine. We clearly saw that he could be contaminating the cutlery.

All we needed to do now was to take the cultures we had taken back to the lab and have them checked out. These were the findings. Camphilobacter, Staph Aureus, Salmonella, e. coli, vibrio an listeria were all present in large quantities within the plaque which we removed from the bread baskets. Our findings were relayed to the company management with the following recommendations. All bread baskets to receive immediate soaking in caustic soda. 2) All bread baskets to be scrubbed individually before putting them onto the aluminium machine,3) all bread baskets to be put into the aluminium machine individually and 4) all bread baskets to receive a weekly soaking in caustic soda. 4) aluminium machine worker was to thoroughly wash his hands and change overalls before helping out anywhere else.

A re check will be conducted in two weeks from the day all the baskets were washed in caustic soda.

kitchen-487973_1920A number of people have contacted me in request that I give some information about sterilizing cooking pots and other kitchen utensils. For most of us in the western world it is not absolutely necessary to sterilize pots as long as we make sure that we wash them thoroughly in very hot water and washing up detergent and a scrubbing pad. In other areas of the world or in situations where pots have been out in field conditions for any period of time, especially in areas where disease is prevalent, the need to continually sterilize pots may be a critical factor in the prevention of food contamination and the recontamination of sick people and the promotion of food hygiene in areas where it does not exist.
Firstly we need to look at the different types of cooking pots. The easiest type of kitchen cooking utensil to sterilize is stainless steel because we can clean it chemically without changing its properties. Other forms of pots present more problems. In Africa it is very common to cook in what, in some places, is called a “poike”. If I am not mistaken this is an Afrikaans word for a cast iron cooking pot. It is cast from a thick sheet of iron or steel and is designed to sit over an open fire. They come in many different sizes and are usually very heavy indeed. They have usually been treated with blackening so they have an outer covering. They also have a thick metal carrying handle that is attached to the rim of the pot across its diameter.
Another form of cooking pot is the aluminum pot. the advantages of aluminum are that it is lightweight and heats up very quickly. The disadvantages of aluminum are that it reacts to just about every form of chemical used to sterilize kitchen equipment. Even the acid in tomatoes, lemon and eggplants remove the essential oxidized layer on aluminum pots. The metal is relatively weak and handles usually fall off after a period of use.
Copper is another form of metal use to make cooking pots but utensils made from copper are normally expensive and in my opinion would not be used in areas of the world which require the sterilization of cooking equipment. In any case we can class it as having very similar properties to aluminum from a cleaning perspective.
Probably the oldest and most traditional way to sterilize all forms of cooking equipment is to boil them in boiling water. Adding some salt to the water will help in the disinfecting process and it will slightly increase the boiling temperature of the water and destroy more bacteria. The advantage of this system is that the pots and pans are immediately ready for use after sterilization. The disadvantages are that the equipment has to be 100% clean before going into the sterilization pot and they require a minimum of thirty minutes to boil before it is safe to take them out. Boiling does not ensure that all types of bacteria will be destroyed and some toxins can survive boiling.
Continuing with the theme of using water to sterilize kitchen equipment another efficient way to sterilize pots and pans is with steam. Steam is much hotter than water it will sterilize things that come into contact with it much more quickly. Using steam under pressure also removes baked on fats and other sediments. Steam treatment is OK for all types of metals but Steam is dangerous and requires that special equipment be worn before working with it safely and efficiently. This equipment should include thick plastic apron, thick plastic or neoprene gloves (not surgical gloves) and eye protection goggles. Like with water the advantage of steam is that equipment can be put straight back into use with no further treatment other than washing with a mild detergent and rinsing with water.
Caustic Soda is the next form of sterilization which I would like to talk about. Caustic Soda destroys all forms or organic material. Concentrated caustic soda needs to be diluted with water and heated to a temperature of no more than 80 degrees Celsius. Caustic soda breaks down at temperatures above 80 degrees Celsius and ceases to be effective.
Great care must be taken with caustic soda because it is very dangerous and can cause serious burns and blindness if it gets into your eyes. People using caustic soda should be properly trained and should also wear protective clothing which should include a thick plastic apron, thick neoprene gloves and a full industrial plastic face mask. This chemical is only suitable for stainless steel, plastic and glass. Other forms of metal will be affected by the chemical reaction of the soda. Aluminum may even be eaten away completely.
The use of caustic soda is also good for removing stubborn cooked on foods. The disadvantage of using soda is that it needs to be washed off dishes completely before they can be used again. Most big kitchen will use a high pressure tray washing machine to do this. If your water supply is not infected you may want to consider rinsing the pots in boiling water to avoid re contamination.
Caustic soda melts the fat in your skin if it spills onto the skin and it causes a slimy film on the surface of the skin until it is properly washed off with cold water. Wash until this feeling has completely gone. Caustic soda is also good for cleaning glass, ceramic and plastic utensils.
Yet another method of sterilizing kitchen equipment is to soak it in hot water and chlorine cleaning powder. Chlorine kitchen powder is also good for removing stubborn stains on ceramics, glass and Pyrex. This type of sterilization will react with aluminum and will remove the oxidized lawyer on the surface of the aluminum which is necessary to remove the toxicity of aluminum. Pots may become unusable if exposed to chlorine powder; therefore, I do not advise using chlorine powder to sterilize aluminum
This form of sterilization requires that equipment be soaked for about three to four hours for good results. Similarly to the use of chlorine must be washed off completely with a mild detergent before reusing treated equipment.

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One job that people really fear doing most in commercial kitchens is cleaning the tough grease off equipment, drains and vents. Why? Because it nearly always involves the use of strong caustic soda based substances.

These substances cause injuries if not handled properly. They can cause blindness if they get into eyes, they can cause breathing problems and they can cause severe chemical burns to the skin. In addition they are a food safety hazard and there is always the risk that they will enter food that is in the work area.

I have used these substances for many years because we really had no other solutions to the cleaning challenges we had to deal with on a daily basis. I used to dread having to use these substances and yet, being the type of person I am I would do most of this work myself because I knew that my staff would cause themselves injury.

However, there is no longer a reason to use such potentially dangerous substances because we have now entered the era of the steam vapour cleaning system. Whereby formally you would spread degreasers onto a surface or scrape a surface for hours on end with a spatula now you can do the same work in a very short space of time using a steam vapour cleaning system.

In commercial kitchens not all work surfaces or cooking trays are stainless steel. It is better if they are but some products use aluminium to make a product less expensive. The advantage with the steam vapour cleaning system is that it cleans any surface, stainless steel, ceramic, aluminium, rubber, plastic, wood or Teflon.

It will clean, grease, grime, mould and lime. What’s more you don’t have to evacuate a twenty meter radius when using it. Once the hard grease and grime is off it becomes easy to maintain clean surfaces because very little time is needed for maintenance. In fact, the only chemical you will regularly need in your kitchen is ordinary washing up detergent. I strongly advise using a steam vapour cleaning system in all types of kitchens. Remember, the cleaner you kitchen is kept, the fewer vermin problems you will have and the easier it becomes to clean your kitchen the cleaner it will be kept.

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