The howling moonsoon and cold weather remind
us of the Chinese delicacy "lap-mei".
In many Chinese restaurants, "lap-mei" dishes
are now back to the centre stage. "Lap-mei",
with its characteristic aroma, often whets our appetite.
But how much do you know about "lap-mei"?
The method of meat curing has been employed
since ancient times. In ancient China, "lap" means "sacrificial
rites" and
very often surplus meat after the rites would be cured
and stored for consumption in times of scarcity. In the old
days, it was a tradition to cure meat in the twelfth month
of the lunar year which served as a delicacy to cerebrate
the Spring Festival. With the invention of refrigerating
equipment, curing as a way to preserve meat has lost its
lustre. Nevertheless, the unique texture and distinct flavor
of traditionally cured meat continue to charm modern people
as an important alternative of fresh meat.
The manufacturing process of "lap-mei"
Raw materials like pork, duck and duck liver must be cleansed
and sliced before the curing ingredients such as salt, sugar,
wine and nitrates or nitrites are added. The mixture is then
placed in chillers to allow thorough distribution of curing
ingredients. The meat is then dried. In the past, the meat
was often air-dried. However, the traditional air-drying
process requires ample space for hanging and loading, not
to mention the unpredictable climate and the long duration
required. Today, the trade largely prefers the method of
hot air-drying and the meat is put in an air-conditioned
chamber at a temperature ranging between 35oC and 40oC to allow
a more rapid vaporization of moisture. Take the preserved
Chinese sausages as an example, the whole drying process
can be completed in 3 to 4 days.
Why are nitrates or nitrites added?
Nitrates or nitrites have a unique place
in meat curing. They can enhance food safety because of
their anti-microbial property especially on Clostridium
botulinum and the inhibition of toxin production.
Clostridium botulinum is a gram-positive, spore-forming,
anaerobic rod that can cause fatal infection. It is known
to exist in anaerobic conditions. Therefore, vacuum-packaged
food such as bacon and canned processed meat can support
growth and toxin production by Clostridium botulinum strains
without causing noticeable smell. In preserved meat especially
meat sausages, spores of the bacteria can germinate, grow
and produce toxin if the temperature is not properly controlled.
Besides, Clostridium botulinum can also grow in food with
high water content.
Nitrates or nitrites also have other important functions.
Firstly, they render the cured meat red-pinkish in colour
by stabilizing the haem in myoglobin through the formation
of nitrosomyoglobin. Secondly, they can delay the process
of oxidative rancidity of meat and, hence, prevent the development
of a rancid smell resulting from prolonged storage.
Health Effects of Nitrate and Nitrite
Nitrate per se has a relatively low toxicity,
whereas nitrite has a more significant effect on the human
body. Nitrates at levels commonly present in food are not
toxic to human However, they can be converted into nitrites
by the intestinal bacteria in human body.
Accidental intake of large amount of nitrite can cause
methaemoglobinaemia. The symptoms include headache, weakness,
breathlessness, and a bluish discolouration of the skin and
mucous membranes called cyanosis. Methaemoglobinaemia resulting
from exposure to food contaminated with nitrite is extremely
rare. The development of methaemoglobinaemia is determined
by the ingested dose and individual susceptibility. For mild
cases of methaemoglobinaemia, the patients usually recover
without specific treatment.
There is currently no evidence that nitrate and nitrite
exposure is associated with the formation of cancer in human.
However, they can combine with amines and amides in food
to form an N-nitrosocompound called nitrosamine. Experiments
on animals reveal that certain nitrosamines are carcinogenic
and epidemiological studies also indicate that certain nitrosamines
are cancer-related.
Advice to the Trade
The trade should adopt the following advices on the purchase
of ingredients, and preparation and storage of "lap-mei":
Purchase of Ingredients
1. Purchase from reliable and reputable
suppliers.
2. Use only fresh meat
and ingredients of high quality.
3. Observe good manufacturing practice and use food grade
nitrates and nitrites.
Preparation Process
1. Do not use nitrate or nitrite excessively. The minimum
amount of nitrate or nitrite sufficient for their intended
purposes should be used.
2. Mix the curing agents well and ensure that they are evenly
distributed on the meat.
3. Make sure contamination does not occur, no matter whether
the "lap-mei" is dried under natural or artificial condition.
Storage Conditions and Period
1. Meat should be properly kept in chillers when being
cured.
2. Store finished "lap-mei" under cool and dry conditions.
3. Despite having gone through the curing process, "lap-mei"
should not be stored for too long lest it becomes spoiled
and produces a rancid smell.
Existing Regulatory Measures
The articles of food which may contain preservative and
the nature and proportion of preservative in each case are
stipulated in the First Schedule to the Preservatives in
Food Regulations made under Section 55 of the Public Health
and Municipal Services Ordinance (Cap 132). As far as "lap-mei"
and preserved Chinese sausages are concerned, the permitted
preservatives include nitrate and nitrite, and their proportions
must not exceed 500 and 200 parts per million respectively.
Any person who contravenes the ordinance shall be liable
to a fine of $50,000 and to imprisonment for 6 months.
Village Casserole
Dish "Poon Choi"
In recent years, enjoying a steaming hot ˇ§poon choiˇ¨
with family members or friends has gained popularity particularly
at times of traditional festivals. The large assortment of food contained
in a pot of ˇ§poon choiˇ¨ guarantees that there are favourite foods
for each person. Many restaurants are offering ˇ§poon choiˇ¨ with various
recipes. Simply place an order with one of the restaurants, and you
can enjoy the delicacies with friends and relatives.
From a food hygiene perspective, ˇ§poon choiˇ¨, which comprises of
different kinds of foods, is in general more complicated to prepare
and cook than a single dish. When preparing ˇ§poon choiˇ¨, the trade
should note the following key points:
1. Purchasing and Collection of Food Ingredients
All food ingredients should be purchased from reputable
and reliable suppliers.
Inspect the food and ingredients upon their delivery
to ensure that the temperatures of chilled and frozen
food are well controlled when they arrive.
2. Storage Facilities and Temperature Control
Observe the ˇ§first-in-first-outˇ¨ principle.
The temperature of chillers should be kept at under 4oC,
and the temperature of freezers should be kept at under
-18oC.
Cooked food should be stored above raw food. Cooked and
raw food should preferably be stored in separate storage
compartments.
3. Food Handling and Cooking
Note the specific date and time for the collection of
ˇ§poon choiˇ¨ by customers and carefully devise a schedule
for preparing poon choi to avoid premature cooking.
Before food handling, all surfaces that will come into
contact with food, such as crockery, cutting boards and
kitchenware, should be thoroughly cleaned and sterilized.
Frozen food should be defrosted by refrigerator or under
running water.
Large chunks of food should be cut into smaller pieces
in advance to facilitate thorough cooking.
Food must be thoroughly cooked.
High-risk food susceptible to contamination, such as sea
food and poached chicken, must be thoroughly cooked and
stored separately to prevent cross contamination.
After being cooked, food ingredients should be either
kept chilled at under 4oC, or kept hot at over 60oC.
Food should be properly covered to prevent cross contamination.
4. Delivery
When delivery of poon choi is required, ensure that:
The container for food delivery must be clean, covered
and equipped with food-warming facilities;
The delivery vehicle must be clean.
5. Personal Hygiene
Before preparing poon choi, keep good personal hygiene:
Wash your hands before preparing food or after using
the toilet, and do not cough or sneeze into food, etc.
No food should be handled by workers with symptoms of
gastroenteritis or infected with flu, etc.
6. Remind Customers of How Poon Choi Should be Handled
Poon choi should be consumed as soon as possible after
collection.
Poon choi not consumed right away should be stored in
a refrigerator. Before it is consumed, poon choi should be
reheated until its core temperature reaches 75oC or above.
As a pot of poon choi is quite voluminous, it will take
a longer time to reheat.
Additional chopsticks should be used for common serving
of food.
Sweeteners
in Food
It is nice to enjoy sunshine and deserts
in holidays. However, many city dwellers are more concerned
about ˇ§keeping fitˇ¨ nowadays.
To cater for the needs of these consumers, food manufacturers
have replaced sugar with sweeteners in their products like soft
drinks, candies, chewing gum and dessert. Sweeteners may soon
become a new ˇ§sweetheartˇ¨ on dinning table, threatening the
dominance of cane sugar.
What is sweetener?
There are two categories of sweeteners, namely naturally
occurring sweetening agents and synthetic compounds. They
are either extracted naturally from plants or chemically
synthesized. Some sweeteners are tens of times more sweet
than cane sugar and only a small quantity of them will suffice
to sweeten food, but the calories they entail are much lower
than that of cane sugar. Since these sweeteners have lower
calories and do not affect the levels of insulin or blood
glucose, they are ideal alternatives for diabetics or people
who want to lose weight.
Are sweeteners safe?
Like all the other food additives, sweeteners have to undergo
stringent safety assessments before they are permitted for
use in food. The Joint Food and Agriculture Organization /
World Health Organization Expert Committee on Food Additives
(JECFA) evaluates the safety of sweeteners based on toxicological
data from animal and human studies and recommends a list of
sweeteners for human consumption. In normal circumstances,
these sweeteners will not pose any harmful effects to humans,
in particular, they are not harmful to growing fetus and do
not induce cancers.
Legislative Controls in
Hong Kong
According to the Sweeteners in Food Regulations
made under the Public Health and Municipal Services Ordinance
(Cap. 132), eight groups of sweeteners are permitted for
use in Hong Kong. Any person who uses non-permitted sweeteners
in any food shall be guilty of an offence and shall be
liable of conviction to a maximum fine of $50,000 and imprisonment
for 6 months.
The eight groups of sweeteners are: Acesulfame Potassium,
Alitame, Aspartame, Aspartame-acesulfame Salt, Cyclamic Acid
(and Sodium, Potassium, Calcium Salts), Saccharin (and Sodium,
Potassium, Calcium Salts), Sucralose and Thaumatin.
Advice to Consumers
Food manufacturers should only use sweeteners stipulated
in the Sweeteners in Food Regulations.
More than one sweetener may be used so as to reduce the
intake of one single sweetener.
According to the Food and Drugs (Composition and Labelling)
Regulations, pre-packaged food must be correctly labelled.
The label must list the additive by its functional class,
its specific name or its identification number under the
International Numbering System for Food Additives.
Facts about "Fabricated
Beef"
Taiwan media reported earlier that the low-priced steaks offered
by a number of local chain steakhouses were fabricated from ˇ§restructured/reconstituted
beefˇ¨. As a result of the wide media coverage, some of these restaurants
ceased offering these kinds of beef product. But the decision was
made purely on commercial ground rather than on food safety ground.
In fact, fabricated steaks are not new. Resembling ordinary steak
in appearance, yet cheaper in price, they are embraced by customers
and have been in common existence in overseas countries.
What is fabricated beef?
Fabricated beef are beef products which have undergone
processes like chopping/mincing, combining/bonding and seasoning.
There are two types of fabricated beef namely restructured
and reconstituted beef. Restructured beef has the connective
tissue removed before bonding and shaping. Reconstituted
beef, on the other hand, comes from beef trimmings mixed
and pressed to shape. Fabricated beef are commonly used for
making sausages and burgers.
How do I know if a steak is
fabricated or natural?
Characteristics of fabricated steaks:
Almost identical in shape and size because the beef
is pressed to shape in the process
Disordered muscle grain can be seen on cross-sections
Less juicy when compared with their natural counterpart
because of the lower moisture-holding capacity
May taste better as additives (e.g. seasoning) might
have been added during processing
Loss of chewy texture and less resilience as the
connective tissue has been destroyed during processing
Characteristics of natural steaks:
Vary in shape and size
Orderly muscle grain
Higher moisture-holding capacity and
therefore more juicy
Tender and chewy texture
What is the risk of consuming fabricated steaks?
During slaughtering, the surface of beef may be contaminated by
bacteria like Esherichia coli O157:H7. Since the fabrication of steaks
involved chopping/mincing of beef, the bacteria on the surface may
find its way into the core of the steak. The more the processing,
the greater the chance of contamination. Moreover, as many people
are in favour of half-cooked steak, it is likely that the bacteria
inside cannot be eradicated. Therefore, fabricated steak must be
thoroughly cooked before consumption.
How to prevent and reduce the risk when purchasing and handling fabricated
steak?
Points to note when purchasing and handling fabricated steak:
Generally speaking, fabricated steaks are frozen food (which
should be kept at a temperature below -18oC). Upon receipt of the
consignment, check the temperature and condition.
After receiving the consignment, store the steak in the freezer
at a temperature below -18oC.
Defrost the steak in the refrigerator at a temperature between
0oC and 4oC.
Fabricated steak should be thoroughly cooked.
Customers ordering half-cooked steak should be notified that
the steak they order is made of fabricated beef which should be
thoroughly cooked for safe consumption.
Last
review date: 24-03-2005