Abstract
1. Excessive intake of salt (sodium) may have higher risk of developing hypertension. Untreated high blood pressure can lead to heart attack, stroke and kidney failure, etc. Siu-mei and Lo-mei food (SMLM) was found to be the sixth major contributors to the total dietary sodium intake of the adult population in Hong Kong.
2. The Centre for Food Safety (CFS) and the Consumer Council (CC) thus has conducted a joint study, and tested the sodium content in selected SMLM available in Hong Kong. This study aims to investigate the level of sodium in these food items; to inform the public on the sodium content in SMLM to enable informed choices; and to urge the food trade to take action to reduce the sodium contents of SMLM in the market.
3. World Health Organization (WHO) recommends that the daily intake of sodium of an average adult should be less than 2000 mg of sodium (approximate 5g salt, i.e. slightly less than 1 level teaspoon of salt). In addition, WHO recommends the average population intake of salt shall be reduced by a relative 30 per cent by 2025.
The Study
4. The study covered 100 samples (10 types), including BBQ pork, roasted pork, roasted suckling pig, roasted goose, roasted duck, soy sauce chicken, Lo-shui goose, Lo-shui goose intestine, Lo-shui goose gizzard and red sausage, collected from Chinese restaurants, Hong Kong style tea restaurants, fast food restaurant, SMLM shops and supermarkets during May to June 2019. Besides, BBQ sauce and Lo-shui marinade were collected when sampling BBQ pork and Lo-shui goose, respectively.
Sodium Content
5. The mean sodium content of study samples are summarised in the table below. Mean sodium content of red sausage ranks the highest, followed by roasted pork, BBQ pork and Lo-shui goose gizzard. The mean sodium contents of the above four food items exceeds the reference level of “High sodium” food (more than 600mg sodium in per 100g food). On the other hand, roasted goose was found to have the lowest mean sodium content.
| Food Item | Sample No. |
Sodium (mg/100g) |
|---|---|---|
| Red Sausage | 10 | 1000 [920-1200] |
| Roasted Pork | 10 | 870 [460-1400] |
| BBQ Pork | 10 | 660 [370-890] |
| Lo-shui Goose Gizzard | 10 | 610 [110-1100] |
| Roasted Suckling Pig | 10 | 550 [380-880] |
| Lo-shui Goose Intestine | 10 | 510 [390-690] |
| Roasted Duck | 10 | 380 [240-530] |
| Lo-shui Goose | 10 | 370 [230-480] |
| Soy Sauce Chicken | 10 | 350 [230-570] |
| Roasted Goose | 10 | 240 [120-480] |
| BBQ Pork Sauce# | 10 | 1600 |
| Lo-shui Marinade# | 10 | 2200 |
6. Findings revealed that there are 1 to 3 times differences in sodium contents when comparing the highest and lowest levels of the ten samples within the same group in most SMLM. Large variations in sodium contents reflect there is room for sodium reduction in SMLM.
7. With regard to sodium intake, applying the mean sodium content in the estimation, an individual will have an intake of 660 mg or 370 mg of sodium from consuming 100g of BBQ pork or Lo-shui goose, respectively. Such intakes of sodium are equivalent to 33% and 19% of WHO's daily recommendation of sodium intake. It is worth to note that these figures have not counted the sodium intake from sauces, if added.
8. To find out the contents of BBQ sauce and Lo-shui marinade, CFS sampled BBQ sauce and Lo-shui marinade at the same time when collecting samples of BBQ pork and Lo-shui goose. Results show that the sodium contents of BBQ sauces and Lo-shui marinade are relatively high. When mimicking the sauce serving practice, there is a 17% increase in sodium content in BBQ pork and 38% in Lo-shui goose.
Fat Content
9. Apart from sodium analysis, total fat and saturated fat analyses were conducted on composite samples of each type of food items. Results in per 100g are summarized in the table below. Roasted goose ranks at the top for total fat content followed by roasted suckling pig, whereas roasted suckling pig has the highest saturated fat content, followed by the roasted goose.
| Food item |
Total Fat |
Saturated Fat |
|---|---|---|
|
Roasted Goose |
37 |
11 |
| Roasted Suckling Pig | 36 | 12 |
| Lo-shui Goose | 29 | 8.2 |
| Roasted Pork | 23 | 7.5 |
| Roasted Duck | 22 | 6.0 |
| Soy Sauce Chicken | 18 | 6.0 |
| Soy Sauce Chicken (without skin) | 6.7 | 2.2 |
| BBQ Pork | 17 | 6.0 |
| Red Sausage | 17 | 5.0 |
| Lo-shui Goose Intestine | 16 | 4.6 |
| Lo-shui Goose Gizzard | 4.8 | 1.3 |
10. Taking the opportunity of this study, the total fat and saturated fat contents of soy sauce chickens with and without skin were tested and compared. It was found that there are 3 times differences in total fat and saturated fat contents between the two versions, showing that there is a health benefit of removing visible fat before food intake.
Advice to the Public
- Maintain a balanced diet with variety. Pay attention to sodium contents in SMLM, choose carefully, and be aware of SMLM with high sodium levels, e.g. red sausage, roasted pork, BBQ pork and Lo-shui goose gizzard.
- Taste the food before dipping in sauce/marinade. Dip lightly in the sauce/marinade, if needed.
- Remove visible fat (e.g. chicken skin) before eating to lower fat intake.
Advice to the Trade
- Be aware of the sodium content of SMLM on sale as it has public health implications. Adding sauce/marinade to SMLM increases the sodium content, therefore, sauce/marinade should be served separately.
- Reduce the sodium content of SMLM through modification of preparation methods and use of ingredients by making reference to the CFS's "Trade Guidelines for Reducing Sodium in Foods".
- When sourcing red sausage from suppliers, ask for nutrition information in order to source a product with lower sodium content.
More Information
10. The related article is published in the CHOICE MAGAZINE (Issue 519, released on 15 January 2020) (Chinese only).
January 2020
Risk Assessment Section
Centre for Food Safety
Food and Environmental Hygiene Department